9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION

 
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
9th WEEK
OF THE YOUNG
RESEARCHER

  QUANTUM SCIENCE:
  LIGHT-MATTER INTERACTION

                Lomonosov Moscow State University
                                Faculty of Physics
                  Moscow, September 23–26, 2019

                         Центр
                         Квантовых
                         Технологий
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
PREFACE

                                                         WELCOME TO THE
                                                         “9TH GERMAN-RUSSIAN WEEK
                                                         OF THE YOUNG RESEARCHER”!
                                                         Dear colleagues from Russia and Germany,                sentations is to facilitate collaboration and to estab­
                                                         We are very delighted to welcome you to our             lish and broaden research networks. The week will
                                                         Ninth Week of the Young Researcher! When we             illustrate how young and experienced scientists
                                                         convened the “German-Russian Year of Science“,          can work across borders with local authorities,
                                                         in 2011, the idea was born to invite young resear­      associations and industry in order to develop new         Dr Andreas Hoeschen

                                                         chers from both countries to come together to dis-      approaches to global challenges.                          German Academic
                                                                                                                                                                           Exchange Service (DAAD)
                                                         cuss current topics of mutual interest. Since then it   This time we discussed particular topics of inte­
                                                                                                                                                                           Head of DAAD Office Moscow
                                                         has grown from strength to strength. The success        rest for quantum science and technology including
                                                                                                                                                                           Managing Director
                                                         of the first week in Kazan encouraged us to turn        aspects form solid-state physics, optics, and photo­
                                                                                                                                                                           of DWIH Moscow
                                                         it into an annual event. The following years we         nics. Special emphasis was given to the challenges of
                                                         met in Ekaterinburg, Novosibirsk, St. Petersburg        the interaction of light with nano-scale solid-state
                                                         and Moscow. The main goal of these meetings             systems as one of the key problems in nano-elec-
                                                         is to foster collaboration among young scientists       tronics and the integration of quantum devices. The
                                                         and researchers who will be setting the agenda of       organizers strove for a good mix of participants at
                                                         scien­tific cooperation between Russia and Germany      different career stages and different fields of exper-
                                                         in the near future.                                     tise including solid-state physics, modern photo­
                                                         Research organizations and institutions of higher       nics, optics of metamaterials, and quantum optics.
                                                         education of both our countries will be presen­         We express our deepest gratitude to the Faculty of
                                                         ting their funding programmes and describing the        Physics of Lomonosov Moscow State University
                                                         platforms that they can offer to both Russian and       for its academic hospitality and kind support. And,
                                                         German PhD students and Postdoctoral resear­            of course, we thank all of the participants, for their    Dr Wilma Rethage
                                                         chers. The overarching principle behind these pre­      involvement and cooperation in this conference.           German Research Foundation (DFG)
                                                                                                                                                                           Head of DFG Office Russia/CIS

IMPRESSUM

Volume of the Conference
“The Ninth German-Russian Week
of the Young Researcher”
Moscow, September 23–26, 2019
Editors:   DAAD/DWIH Moscow
           DFG Moscow
Edited by: Julia Ilina (DFG)
Layout by: “MaWi group” AG / Moskauer Deutsche Zeitung
Photos by: DWIH / Sergey Teplyakov
Moscow, July 2020

Supported by Federal Foreign Office
                                                                                                                                                                                                       1
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                                       TABLE OF CONTENTS

TABLE OF CONTENTS

PREFACE CONTENTS                                                              Dr Maria Chekhova                                                           Aleksey Kazakov                                                             Dr Michael Stefszky
                                                                              Max-Planck Institute for the Science of Light, Erlangen;                    Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 24          University of Paderborn  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 38
Dr Andreas Hoeschen / Dr Wilma Rethage  .  .  .  .  .  .  .  .  . 1
                                                                              University of Erlangen-Nürnberg;                                            Maria Kroychuk                                                              Professor Dr Aleksey Toropov
WELCOMING ADDRESSES                                                           Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 13          Lomonosov Faculty of Physics, Moscow State University  .  .  . 25           Ioffe Institute, St. Petersburg  .  .  .  .  .  .  .  .  .  .  .  .  . 39
                                                                              Dr Mikhail Durnev                                                           Professor Dr Sergei Kulik                                                   Aleksandr Vaskin
Professor Dr Andrey Fedyanin
                                                                              Ioffe Institute, St. Petersburg  .  .  .  .  .  .  .  .  .  .  .  .  . 14   Centre of Quantum Technologies, Faculty of Physics,                         Institute of Applied Physics, Abbe Centre of Photonics,
Vice Rector, Lomonosov Moscow State University  .  .  .  .  .  . 4            Max Ehrhardt                                                                Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 26          Friedrich Schiller University of Jena  .  .  .  .  .  .  .  .  .  .  .  . 40
Beate Grzeski                                                                 Univerity of Rostock, Institute for Physics  .  .  .  .  .  .  .  .  . 15   Jano Gil Lopez                                                              Sebastian Weidemann
Deputy Head of Mission, German Embassy Moscow  .  .  .  .  . 5                Anna Fedotova                                                               Integrated Quantum Optics, Paderborn University  .  .  .  .  .  . 26        Institute of Physics, University of Rostock  .  .  .  .  .  .  .  .  . 41
Dr Michael Harms                                                              Institute of Applied Physics, Abbe Centre of Photonics, Jena  .  . 16       Professor Dr Boris Luk’yanchuk                                              Professor Dr Dieter Weiss
Director Communications,                                                      Professor Dr Andrey Fedyanin                                                Division of Physics and Applied Physics, School of Physical                 Experimental and Applied Physics, University of Regensburg  .  . 42
German Academic Exchange Service (DAAD) Bonn  .  .  .  .  .               6                                                                               and Mathematical Sciences, Nanyang Technological University;                Jonas Zipfel
                                                                              Faculty of Physics, Lomonosov Moscow State University  .  .  . 17
Professor Dr Frank Allgöwer                                                                                                                               Faculty of Physics, Lomonosov Moscow State University  .  .  . 27           Department of Physics, University of Regensburg  .  .  .  .  .  . 43
                                                                              Alessandro Ferreri
Vice President of the German Research Foundation (DFG);                                                                                                   Lukas J. Maczewsky
                                                                              Integrated Quantum Optics, Paderborn University  .  .  .  .  .  . 17                                                                                    SCIENCE ORGANISATIONS
Institute for Systems Theory and Automatic Control,                                                                                                       Universität Rostock; Friedrich-Schiller-Universität Jena  .  .  .  . 28
                                                                              Assegid M. Flatae
University of Stuttgart  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   7                                                                               Gregor Oelsner                                                              Faculty of Physics Moscow Lomonosov State University  .  .  . 44
                                                                              University of Siegen, Laboratory of Nano-Optics and Cµ  .  .  . 18
                                                                                                                                                          Leibniz Institute of Photonic Technology, Jena  .  .  .  .  .  .  . 30      German Centre for Research and Innovation (DWIH)  .  .  .  .  . 46
CONFERENCE SUMMARY                                                            Ilia Fradkin
                                                                                                                                                          Markus Plankl                                                               German Research Foundation (DFG)  .  .  .  .  .  .  .  .  .  .  . 47
                                                                              Skolkovo Institute of Science and Technology, Moscow;                       Department of Physics, University of Regensburg  .  .  .  .  .  . 31
Dr Cosima Schuster                                                                                                                                                                                                                    German Academic Exchange Service (DAAD)  .  .  .  .  .  .  . 48
                                                                              Moscow Institute of Physics and Technology  .  .  .  .  .  .  .  . 19
                                                                                                                                                          Anna Popkova                                                                The Helmholtz Association  .  .  .  .  .  .  .  .  .  .  .  .  .  . 49
Physics and Chemistry,                                                        Dr Aleksandra Galeeva
German Research Foundation (DFG)  .  .  .  .  .  .  .  .  .  .  .         9                                                                               Faculty of Physics, Lomonosov Moscow State University  .  .  . 32           The Fraunhofer-Gesellschaft  .  .  .  .  .  .  .  .  .  .  .  .  .  . 50
                                                                              Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 20          Maksim Rakhlin
Professor Dr Sergey Kulik                                                                                                                                                                                                             Freie Universität Berlin  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 51
                                                                              Aleksandra Gartman                                                          Ioffe Institute, St. Petersburg  .  .  .  .  .  .  .  .  .  .  .  .  . 33
Centre of Quantum Technologies, Faculty of Physics,                                                                                                                                                                                   The University Alliance Ruhr Liaison Office Moscow  .  .  .  .  . 52
                                                                              Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 20          Sergey Samoylenko
Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  .  . 9                                                                                                                                                                  Contact Office of the Ministry of Culture and Science
                                                                              Professor Dr Vladimir Gavrilenko                                            Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 34          of the Federal State of North Rhine-Westphalia  .  .  .  .  .  .  . 53
PARTICIPANTS OF THE WEEK                                                      Institute for Physics of Microstructures RAS,                               Anatoly Shukhin                                                             Russian Science Founation (RSF)  .  .  .  .  .  .  .  .  .  .  .  . 54
OF THE YOUNG RESEARCHER                                                       Nizhny Novgorod  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 21    Zavoisky Physical-Technical Institute,
                                                                              Professor Dr Evgeny Il’ichev                                                Kazan Scientific Centre of the Russian Academy of Sciences  .  . 34         LIST OF PARTICIPANTS  .  .  .  .  .  .  .  .  .  .  .  .  . 55
Professor Dr Mario Agio
                                                                              Leibniz Institute of Photonic Technology;                                   Nikolay Skryabin
University of Siegen, Laboratory of Nano-Optics and Cµ  .  .  . 10                                                                                                                                                                    PROGRAMME  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58
                                                                              Novosibirsk State Technical University  .  .  .  .  .  .  .  .  .  . 22     Quantum Technologies Centre, Faculty of Physics,
Dr Sascha Agne                                                                Professor Dr Nicolas Joly                                                   Lomonosov Moscow State University  .  .  .  .  .  .  .  .  .  . 35          ARCHIVE OF PUBLICATIONS  .  .  .  .  .  .  .  .  .  .  . 64
Max-Planck-Institute for the Science of Light, Erlangen  .  .  .  . 11        Friedrich Alexander University;                                             Florian Sledz
Dmitry Akat’ev                                                                Max-Planck Institute for the Science of Light  .  .  .  .  .  .  .  . 23    Laboratory of Nano-Optics and Cµ, University of Siegen  .  .  .  . 36
Kazan E. K. Zavoisky Physical-Technical Institute  .  .  .  .  .  . 11        Professor Dr Alexey Kalachev                                                Professor Dr Isabelle Staude
Susanne Candussio                                                             Zavoisky Physical-Technical Institute,                                      Institute of Applied Physics, Abbe Centre of Photonics,
University of Regensburg, Terahertz Centre  .  .  .  .  .  .  .  . 12         Kazan Scientific Centre of RAS; Kazan Federal University  .  .  . 23        Friedrich Schiller University Jena  .  .  .  .  .  .  .  .  .  .  .  . 37

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9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                       WELCOMING ADDRESS

                                DEAR LADIES AND GENTLEMEN!                                                                                     DEAR PROFESSOR FEDYANIN,
                                Today we are opening the Ninth Russian-German          the long-­standing and most important scientific
                                                                                                                                               DEAR PROFESSOR ALLGÖWER,
                                Week of the Young Researcher at the Faculty of
                                Physics of Lomonosov Moscow State University.
                                                                                       partners of MSU. So, I am very pleased to open
                                                                                       a joint event here at the Faculty of Physics with
                                                                                                                                               DEAR DR HARMS,
                                Оur conference is dedicated to quantum technolo-       colleagues from Germany.                                LADIES AND GENTLEMEN!
                                gies. On behalf of the University, I am very glad to   During the conference, there will be reports and
                                welcome the respected members of the Presidium,        discussions on various topics related to quantum        I am pleased to welcome you to the 9th iteration        Since March 2019, more than 90 bilateral activi-
                                all participants and guests of the Russian-German      technologies – quantum computing and commu-             of the “German-Russian Week of the Young Re-            ties have been registered on the website of the Sci-
                                Week, especially those who are just starting their     nications, solid state physics, optics, and photo­
Professor Dr Andrey Fedyanin                                                                                                                   searcher”, which has become a cornerstone of the        ence Year. This once again underscores the inten-          Beate Grzeski
                                way in science. I think, young scientists are basi-    nics. Also, we will have a number of reports devo­ted
Vice Rector,                                                                                                                                   German-Russian science calendar.                        sity of cooperation between German and Russian             Deputy Head of Mission,
                                cally the force that moves science forward, they       to the problems of interaction of a solid state and
Faculty of Physics, Lomonosov                                                                                                                                                                          universities.                                              German Embassy Moscow
                                are the ones who will make scientific discoveries                                                              Also this year’s “Week of the Young Researcher”
Moscow State University                                                                light. Separately, I am announcing with great in-
                                in the future. Our mission, the mission of more ex-                                                            will serve to develop new cooperation projects          All these activities contribute to creating a solid
                                                                                       terest a poster section where young scientists will
                                perienced scientists, is to help them and create all                                                           and partnerships, in particular between young           foundation for a substantial relationship between
                                                                                       present their research.
                                possible conditions to make their work productive.                                                             scientists, thus making German-Russian science          our two countries. The German-Russian Week of
                                                                                       I wish everyone efficient and interesting work          cooperation even more dynamic and intense.              the Young Researcher is one of the finest examples
                                At the opening of this event, it is necessary to say   and hope that the 9th Russian-German Week will                                                                  for this partnership.
                                that international cooperation is extremely im-        mark the beginning of active collaborative work         In this respect, I would like to thank the German
                                                                                                                                               Academic Exchange Service, the German Center            Since 2011, the Week of the Young Researcher
                                portant for the development of science all around      for the young scientists from different countries.
                                                                                                                                               for Research and Innovation and the German Re-          has been organized annually in different cities in
                                the world, especially if we are talking about such     I hope that the exchange of ideas and scientific
                                                                                                                                               search Foundation and all the people who have           Russia covering various important topics. This
                                a rapidly developing industry as quantum sci-          discussions that will take place throughout the
                                                                                                                                               made this event possible, for their support and         year, the focus is set on Quantum Science, which
                                ence. Moscow State University cooperates with          days of the event will be useful for the further de-
                                                                                                                                               contributions.                                          is an integral part of the development of modern
                                many scientific and educational organizations          velopment of individual scientific projects and the
                                                                                                                                                                                                       technologies.
                                from different countries and Germany is one of         global quantum technology industry.                     Scientific cooperation between Russia and Ger-
                                                                                                                                               many has a broad basis, ranging from exchanges          Working together, benefiting from each other’s
                                                                                                                                               of students and young scientists, partner univer-       strengths and skills brings advantages both to
                                                                                                                                               sities, joint research institutes and research groups   Germany and Russia and keeps us competitive on
                                                                                                                                               to cooperation within the framework of voca-            a global scale. Physics is a field where Russia tradi-
                                                                                                                                               tional training. In this vein so we work together       tionally excels in.
                                                                                                                                               on many concrete projects such as the European          I´m grateful that this year’s event is being organ-
                                                                                                                                               XFEL or the Arctic research expedition MOSAiC.          ized at Russia’s leading university – Lomonosov
                                                                                                                                               Because of the importance of science and educa-         Moscow State University. I would like to thank the
                                                                                                                                               tion for our bilateral relations, we agreed in 2018     Faculty of Physics for their kind cooperation and
                                                                                                                                               on a German-Russian Roadmap for Cooperation             hospitality. I hope that the conference will con-
                                                                                                                                               in Education, Science, Research and Innovation          tribute to an ever closer cooperation between your
                                                                                                                                               and launched the German-Russian Year of High-           University and German research institutions.
                                                                                                                                               er Education Cooperation and Science 2018–              May this year’s Week be successful and further
                                                                                                                                               2020. I encourage you to participate actively in        contribute to the good tradition of cooperation
                                                                                                                                               both ini­tiatives.                                      bet­ween German and Russian scientists!

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9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                 WELCOMING ADDRESS

                           DEAR VICE RECTOR PROFESSOR FEDYANIN,                                                                            LADIES AND GENTLEMEN,
                           DEAR DEPUTY HEAD OF MISSION,                                                                                    DEAR PARTICIPANTS,
                           DEAR MS. GRZESKI,                                                                                               We were very pleased that you have accepted the        or metrology, requires fundamental understanding
                           DEAR VICE PRESIDENT                                                                                             invitation of the joint initiative of DAAD, the Ger-
                                                                                                                                           man Academic Exchange Service, and DFG, the
                                                                                                                                                                                                  at the quantum level. The decreasing size of basic
                                                                                                                                                                                                  circuits in modern micro- and nano-electronics
                           PROFESSOR ALLGÖWER,                                                                                             Deutsche Forschungsgemeinschaft, under the roof        leads to the necessity to consider quantum effects
                                                                                                                                           of the German Centre for Research and Innova-          and to apply quantum science approaches for the

Dr Michael Harms
                           DEAR PARTICIPANTS                                                                                               tion in Moscow, as well as the Moscow State Uni-       careful analysis of their properties. Experimental
                                                                                                                                                                                                                                                            Professor Dr Frank Allgöwer
                                                                                                                                           versity and the Quantum Technologies Centre.
Director Communications,   OF THE 9TH GERMAN-RUSSIAN WEEK                                                                                  Our DFG delegation was more than happy to have
                                                                                                                                                                                                  studies with ultrahigh resolution in space and time
                                                                                                                                                                                                  and advanced theoretical descriptions are manda-
                                                                                                                                                                                                                                                            Vice President of the German
German Academic Exchange                                                                                                                                                                                                                                    Research Foundation DFG
Service (DAAD) Bonn        OF THE YOUNG RESEARCHER,                                                                                        welcomed you to the 9th Week of the Young Re-
                                                                                                                                           searcher in Moscow!
                                                                                                                                                                                                  tory. In this sense, one of the most important issues
                                                                                                                                                                                                  in modern quantum science is the interaction of
                                                                                                                                                                                                                                                            Institute for Systems Theory
                                                                                                                                                                                                                                                            and Automatic Control,
                                                                                                                                           After being focused on issues of energy, health,       optical fields with micro- and nanoscale solid-state      University of Stuttgart
                           It gives me great pleasure to welcome you all to      partnership opportunities with the German science         aerospace, history, mathematics, urban studies         circuits. The ability to manipulate these circuits
                           this year’s Week on behalf of the DAAD, the Ger-      and innovation community. Our aim is to connect           and biomedicine, as well as chemistry over the         by light will have amazing possibilities for study-
                           man Academic Exchange Service. First of all,          scientists, scholars, policy makers and business          last nine years, this year’s topic encompasses var-    ing fundamental questions as well as applications.
                           I would like to thank very warmly our host, the       people across borders and facilitate a fruitful and       ious aspects of quantum science and technology         Examples are the generation of spin-polarized
                           Lomonosov Moscow State University. We highly          lively dialogue. A major focus of our activities lies     including solid-state physics, optics of metama-       states in semiconductor nanostruc­tures, the precise
                           appreciate the opportunity to jointly organise this   on exploring as to how scientists might jointly           terials, modern photonics, and quantum optics.         manipulation of micro- and nanoparticles, and the
                           outstanding German-Russian science event at Rus­      push the frontiers of knowledge and find new ways         Special emphasis will be given to the challenges of    non-trivial susceptibility of metastructures. In the
                           sia’s leading university.                             to put their knowledge to practical use. This is in       the interaction of light with nano-scale solid-state   future, quantum science and technologies should
                           Coming together at this very special and presti­      many ways also what the German-Russian Week               systems as one of the key problems in nano-elec-       lead to practically significant scientific and tech-
                           gious institution is a strong manifestation of the    of the Young Researcher is all about.                     tronics and the integration of quantum devices.        nical results in the areas of spintronics, photonics,
                           promising development of the German-Russian           The German Research Foundation has taken the              Taking into account the growing population and         metamaterials, quantum op­tics, quantum comput-
                           relationship in science and academia. Ms Grzeski      le­ad again to identify a cutting-edge topic: light-­     rising living standards, the world is faced with an    ing and quantum commu­nications.
                           mentioned already the German-Russian Year of          matter-interaction in quantum science. Thanks to          increasing demand of power consumption, da­ta          There is no doubt that this broad range of research
                           Higher Education and Science Partnerships and         that effort and the immediate positive response of        storing and communication. Modern techno­lo­gies       questions is of high interest to many researchers
                           the strategic German-Russian Roadmap. We are          many experts in this field, we are able to welcome        rely on devices with cleverly designed electronic      worldwide. The DFG with its annual budget of
                           optimistic that these joint initiatives will signi­   today 21 junior and senior scientists from German         and optical properties. Finding new functionalities    more than 3 billion euros finances and supports
                           ficantly further German-Russian cooperation in        universities and research institutions. They will dis-    in quantum science, for example, for sensors, in-      a large number of interdisciplinary projects in
                           science and research.                                 cuss most relevant aspects of their research with         formation storage and processing, cryptography,        this field of research at German universities and
                           The DAAD is delighted to be able to contribute        their Russian counterparts from the Moscow State
                           to these ongoing endeavours – in the capacity as      University and other highly distinguished universi-
                           coordinator of the German-Russian Year and, of        ties and research facilities from all over Russia. I am
                           course, through our day-to-day work as a fund-        very confident that the different research angles
                           ing and facilitating organisation for international   und experiences will generate an exciting exchange
                           academic exchange and cooperation. Above all,         of insights and approaches.
                           we understand that in the end only the scientists     The Week is an annual flagship event of the Mos-
                           and academics themselves can build and develop        cow DWIH and each of it is a topically unique
                           the collaboration that delivers on the demand for     one-­off occasion. Nevertheless, it offers the op-
                           new scientific insights and innovation.               portunity for longer-lasting inspiration and fur-
                           For this reason, all German science organisations     ther academic engagement. As to that, I would
                           established the German Centres for Research and       also like to recommend visiting the Science Café
                           Innovation (DWIH) which are strongly supported        on Wednesday where the German Centre for Re-
                           by the German Federal Foreign Office. The DAAD        search and Innovation and its organisations will
                           has taken over the management of the currently        provide information about support and funding
                           five centres worldwide. The fact that Moscow          for German-Russian science collaboration.
                           hosts one of them emphasises the huge potential       I would like to thank everybody for participating,
                           we recognise in science collaboration with Russia.    especially those of you who undertook a longer
                           With the DWIH-network, we provide a platform          journey – and I hope that all of you will enjoy and
                           for a global exchange of information and ideas on     make the most of the Week!

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9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                    CONFERENCE SUMMARY

                                                                                                                                 WHAT WILL WE BE TALKING ABOUT:
                                                                         First of all, it is an important event of the ongoing
                                                                         German-Russian Year of Higher Education Coop-
                                                                         eration and Science 2018-2020. In fact, the pro-
                                                                         gramme itself was incepted nine years ago during
                                                                         the German-Russian Year of Science in 2011/2012,        LIGHT-MATTER INTERACTION
                                                                         which led to an annual event since then. We in-
                                                                         tended to provide early career researchers with a
                                                                         platform for exchange on research topics of global
                                                                         interest. Also, the format itself follows a very old
                                                                         tradition in our bilateral collaboration. Namely,
                                                                         in the 1920s, the DFG’s predecessor organisation,       Taking into account the rising living standards,       in semiconductor nanostructures, and the shaping
                                                                         together with the Soviet Academy of Sciences,           the world is faced with an increasing demand for       of light by metamaterials or metasurfaces. In addi-
                                                                         organised joint science weeks. These bilateral re-      less power consuming data storage and commu-           tion, ultrafast laser pulses with intense laser fields
                                                                         search weeks, which were conducted in the nat-          nication techniques. Modern technologies rely on       provide a unique opportunity to study and to ma-
                                                                         ural sciences (1927), in history (1928), in engi-       cleverly designed materials and their electronic       nipulate solid-state systems.
                                                                         neering sciences (1929), and in medical sciences        and optical properties. The decreasing size of basic
                                                                                                                                                                                        A distinctive feature of modern science about the
                                                                         (1932) proved to be an outstanding cooperative          circuits in modern electronics leads to the necessi-
                                                                                                                                                                                        interaction of light with matter is the fact that
                                                                         instrument.                                             ty of considering quantum effects for their further
                                                                                                                                                                                        both light and matter are considered at the level of
                                                                                                                                 improvement. Finding new functionalities, for ex-
                                                                         Second, we owe our gratitude to the Lomonosov                                                                  individual quantum objects. This is, perhaps, the
                                                                                                                                 ample, for information processing, ultrasensitive
                                                                         University and its Rector, Mr Sadovnichy, and the                                                              main difference between the physics of the 20th
                                                                                                                                 sensors, inherently secure communication and
                                                                         Faculty of Physics with its Vice-Rector Mr Fedya-                                                              and the current centuries. Enormous successes,           Dr Cosima Schuster
                                                                                                                                 cryptography, or precision metrology, requires an
                                                                         nin, in particular for setting up and hosting this                                                             first of all, in the technology and equipment avail-     Physics and Chemistry,
                                                                                                                                 understanding and the access to the quantum-me-
                                                                         event and thus giving young scientists the oppor-                                                              able in the modern experiment, enable scientists         German Rersearch
                                                                                                                                 chanical level. Since the beginning of the 20th
                                                                         tunity to directly engage in such a professional ex-                                                           to study and control the properties of individual        Foundation (DFG)
                                                                                                                                 century, quantum mechanics forms the theoreti-
                                                                         change. In October 2018, the DFG-President Pe-                                                                 quantum particles – photons, atoms, ions, mol-
                                                                                                                                 cal basis for our understanding of the microscopic
                                                                         ter Strohschneider and Rector Sadovnichy signed                                                                ecules, etc. These opportunities are widely used
                                                                                                                                 world. At the core of modern quantum science,
                                                                         a joined agreement on intensifying our bilateral                                                               by the successes of modern physics of the inter-
                                                                                                                                 there is the notion of entanglement, a feature with-
                                                                         institutional cooperation. We consider this year’s                                                             action of light with matter in such areas as quan-
                                                                                                                                 out a classical analogue. For example, properties of
                                                                         week to be an important step towards this goal.                                                                tum computing, quantum communication, and
                                                                                                                                 entangled particles are perfectly correlated even if
                                                                         Yet, project-wise the DFG has always been active                                                               quantum sensorics – in everything that we know
                                                                                                                                 there is a large distance between them. This cor-
                                                                         in supporting research projects – about 113 bilat-                                                             as "Quantum Technology".
                                                                                                                                 relation is responsible for astonishing phenomena.
                                                                         eral cooperation projects at the MSU (30 of them        For further developments, experimental studies         Quantum properties of light are prominent in sin-
                                                                         co-funded by RFBR and 10 by RSF) in the peri-           providing ultrahigh resolution on the atomic scale     gle photon sources which are necessary for the re-
                                                                         od from 2008 to 2018, which is more than at any         and advanced theoretical descriptions are manda-       alization of quantum repeaters. Trapped ions and
                                                                         other Russian research institution. The two largest     tory. Yet, individual demonstrators of quantum de-     single molecules like pentacene can be used as
                                                                                                                                                                                                                                                 Professor Dr Sergey Kulik
                    research institutes with funding instruments ran­    German-Russian long-term projects at MSU were           vices have been already built with semiconducting,     sources of single photons; but also colour centers
                                                                                                                                                                                                                                                 Quantum Technology Centre,
                    ging from individual grants to coordinated long-     two International Research Training Groups from         superconducting, ionic and cold atom systems.          created by nitrogen vacancies in diamond or sem-
                                                                                                                                                                                                                                                 Faculty of Physics, Lomonosov
                    term programmes such as Research Training Groups     the life sciences with the universities of Gießen                                                              iconductor quantum dots are widely investigated          Moscow State University
                                                                                                                                 As light is often used as a tool, the interaction of
                    (Graduiertenkollegs) or Collaborative Research       and Marburg (GRK 1384, 2006-2015) and the                                                                      in this context. Pairs of single photons are created
                                                                                                                                 optical fields with matter is intensively studied
                    Cen­tres (Sonderforschungsbereiche).                 Munich universities LMU and TUM (GRK 1563,                                                                     in spontaneous parametric down-conversion and
                                                                                                                                 in current quantum science. An example for in-
                                                                         2009-2013). In addition to the life sciences, pro-                                                             spontaneous four-wave mixing. They are essential
                    When it comes to the German-Russian coopera-                                                                 triguing cooperative behavior based on quantum
                                                                         jects in soil and plant sciences, in mathematics                                                               for quantum key distribution, a cryptography pro-
                    tion, physics profits tremendously from the annu-                                                            effects is superradiance, where the collective re-
                                                                         and astrophysics, in experimental and theoretical                                                              tocol using quantum mechanics, which is already
                    al bilateral DFG calls with the Russian Foundation                                                           sponse of an ensemble of emitters irradiated with
                                                                         physics as well as in polymer chemistry and pro-        light is fundamentally different from the scatter-     commercially available.
                    for Basic Research (RFBR) and the Russian Sci-       cess engineering were funded.                           ing properties of individual particles. Light-matter   All in all, light-matter interaction is the key ingre-
                    ence Foundation (RSF). Those thematically open
                                                                         Finally, I would like to thank the German Em-           interaction plays also an important role in a wide     dient in implementing quantum devices and ap-
                    calls foster long-term cooperation in physics be-
                                                                         bassy, always represented at the weeks by their         range of different quantum systems, from the trap-     plications. Modern quantum science continues to
                    tween Russian and German scientists. Russia still
                                                                         ambassadors or their deputies, for the continuing       ping and precise manipulation of atoms and nan-        be a very active field, in particular, where quantum
                    is and will stay one of the most important cooper-
                                                                         support of this format. You have long recognised        oparticles, the generation of spin-polarized states    optics and solid-state physics are merging.
                    ation partners for us in physical sciences.
                                                                         that these scientific meetings foster research co­
                    Apart from the topical aspects of this week, allow   operation and make a valuable contribution to de-
                    me to point out that this year’s research week is    veloping trust and partnerships among the early
                    deeply embedded into our German-Russian part-        career researchers and future generations of scien-
                    nership in many ways.                                tists from both our countries.

8                                                                                                                                                                                                                                                                                9
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                             PARTICIPANTS

PARTICIPANTS OF THE WEEK                                                                                                                       Nonlinear Polarimetry
OF THE YOUNG RESEARCHER                                                                                                                        with Parametric Down-Conversion
                                                                                                                                               Sascha Agne1, Santiago López Huidobro1,2, Maria V. Chekhova1,2,3
                                                                                                                                               1
                                                                                                                                                 Max-Planck-Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
                                                                                                                                               2
                                                                                                                                                 Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 7/B2,
                                                                                                                                                 91058 Erlangen, Germany
                                                                                                                                               3
                                                                                                                                                 Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia

                                   Ultrafast Coupling of Light                                                                                 Polarization is arguably the most accessible degree     nonlinear polarizers is more profound, however,        Dr Sascha Agne
                                                                                                                                                                                                                                                              Max-Planck-Institute
                                                                                                                                               of freedom of light fields [1]. Using readily availa-   and fundamentally changes the operating princi-
                                   with Quantum Emitters                                                                                       ble polarizers of various kinds, a beam of light is     ple of a polarimeter. Here we discuss this principle   for the Science of Light, Erlangen

                                                                                                                                               easily polarized and analyzed. A pair of polarizers     and demonstrate a polarimeter that consists entire-
                                   M. Agio1,2                                                                                                  forms a polarimeter, which permits measurements         ly of nonlinear polarizers. Our first experimental
                                   1
                                     Laboratory of Nano-Optics and Cµ, University of Siegen, 57072 Siegen Germany                              of light field rotations induced by various physical    results using parametric down-conversion indicate
                                   2
                                     National Institute of Optics (INO-CNR), 50125 Florence, Italy                                             processes with great precision. Ever since Malus’       extinction ratios many orders of magnitude better
                                                                                                                                               original studies on polarization in the early 19th      than available with linear optical polarizers.
                                   The modification of light-matter interaction by        enab­le the investigation of short-lived coherence   century, polarizers are almost exclusively made of      [1] Born M, Wolf E Principles of Optics. Cam-
                                   metal nanostructures has gained a considerable         and quantum effects in nanoscopic systems under      linear optical media. Though secondary to their             bridge University Press 2013.
Professor Dr Mario Agio            attention across a broad range of topics [1]. Our      ambient conditions [3,4].                            primary role as frequency converters [2], nonlin-       [2] Boyd R Nonlinear Optics. Academic Press 2008.
University of Siegen,              interests focus on the interrogation of single quan-
Laboratory of Nano-Optics and Cµ                                                          [1] Agio M, and Alù A., Optical Antennas (Cam-       ear optical processes also polarize light fields. In-   [3] Saltiel SM, Yankov PD, Zheludev NI Second
                                   tum emitters, where we have shown that huge en-
                                                                                              bridge University Press, 2013)                   tuitively, one expects the nonlinearities to promote        harmonic generation as a method for polariz-
                                   hancements of the spontaneous emission rate can
                                                                                          [2] Agio M., Optical antennas as nanoscale reso-     quantitative advantages such as improved degree of          ing and analyzing laser light. Applied Physics
                                   coexist with large quantum efficiencies [2]. This
                                                                                              nators, Nanoscale 4, 692 (2012)                  polarization [3]. The difference between linear and         B 1987; 42: 115–119.
                                   makes such hybrid systems appealing for explor-
                                                                                          [3] Chen C.-W., Mohammadi A., Baradaran Gha­
                                   ing ultrafast quantum phenomena on the nano-
                                   scale and for developing quantum technologies.             semi A.H. and Agio M., Ultrafast coherent
                                   We discuss configurations that strongly increase           nanoscopy, Mol. Phys. 111, 3003 (2013)
                                   light-matter interaction and address quantum           [4] Flatae A.M., Tantussi F., Messina G.C., De An­
                                                                                              gelis F., Agio M., Plasmon-assisted suppres-
                                                                                                                                               Generation of Time-Bin Qudit
                                   coherence and nonlinear optical processes that
                                   occur despite the existence of large dephasing             sion of surface trap states and enhanced band-   Based on Spontaneous Parametric
                                   rates. Next, we propose approaches that combine            edge emission in a bare CdTe quantum dot,
                                   these findings with ultrafast techniques in order to       J. Phys. Chem. Lett. 10, 2874 (2019)             Down-Conversion
                                                                                                                                               D.O. Akat’ev1, A.A. Kalachev1,2, I.Z. Latypov1, A.V. Shkalikov1, D.A Turaykhanov1
                                                                                                                                               1
                                                                                                                                                 Kazan E. K. Zavoisky Physical-Technical Institute, 420029 Kazan, Russia, Sibirsky tract, 10/7
                                                                                                                                               2
                                                                                                                                                 Kazan Federal University, 420008 Kazan, Russia, Kremlevskaya st., 18

                                                                                                                                               Single photons are actively used as information         In our work, we used a lithium niobate crystal         Dmitry Akat’ev
                                                                                                                                               carriers in applications of quantum optics and          doped of magnesium oxide LiNbO3: MgO (5%)              Kazan E. K. Zavoisky
                                                                                                                                               quantum informatics. One of their main proper-          (PPLN), the modulation period of which is              Physical-Technical Institute
                                                                                                                                               ties is the inability to read information without       Λ = 7.47 μm and the length is 25 mm. At a pump
                                                                                                                                               destroying the quantum state. The use of multi-         wavelength of 532 nm, photon pairs are generated
                                                                                                                                               dimensional entangled states can increase the in-       at wavelengths of 867 nm and 1377 nm during the
                                                                                                                                               formation capacity [1]. In addition, high-dimen-        0-type synchronism SPR (eee type) at the temper-
                                                                                                                                               sional states are resistant to eavesdropping attack     ature of 85 degrees Celsius. As a result, photons
                                                                                                                                               in the quantum key distribution protocols [2] and       Δνmod = 73 MHz at a wavelength of 867 nm were
                                                                                                                                               a strong violation of the generalized Bell inequal-     obtained [5]. For generation of time-bin qubits we
                                                                                                                                               ities [3] with possible applications in device-inde-    used scheme presented in [6]. First results of this
                                                                                                                                               pendent quantum cryptography [4] and random             study will be presented at the poster.
                                                                                                                                               number generation. In our work, we consider the         [1] Walborn SP, et al. Quantum key distribution
                                                                                                                                               possibility of generating high-dimensional states           with higher-order alphabets using spatially
                                                                                                                                               based on time coding via spontaneous parametric             encoded qudits. Physical review letters 2006;
                                                                                                                                               down-conversion.                                            96.9: 090501.

10                                                                                                                                                                                                                                                                                           11
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                          PARTICIPANTS

                            [2] Cerf NJ, et al. Security of quantum key distri-
                                bution using d-level systems. Physical Review
                                                                                   [5] Akat’ev DO, et al. Generation of narrow-band
                                                                                       single-photon states via spontaneous para-
                                                                                                                                           Generation of Entangled Photons
                                Letters 2002; 88.12: 127902
                            [3] Kaszlikowski D, et al. Violations of local real-
                                                                                       metric down-conversion for quantum mem-
                                                                                       ories in doped crystals. Quantum Electronics
                                                                                                                                           without Momentum Conservation
                                ism by two entangled N-dimensional systems             2018; 48.10: 902.
                                                                                                                                           A. Cavanna1,2, C. Okoth1,2, J. T. Santiago Cruz1,2, M. V. Chekhova1,2,3
                                are stronger than for two qubits. Physical Re-     [6] Islam NT et al. Provably secure and high-           1
                                                                                                                                             Max-Planck Institute for the Science of Light, Erlangen, Germany
                                view Letters 2000; 85.21: 4418.                        rate quantum key distribution with time-bin         2
                                                                                                                                             Friedrich-Alexander University of Erlangen-Nürnberg, Germany
                            [4] Barrett J, Hardy L, Kent, A. Physical review           qudits. Science advances 2017; 3.11: e1701491.      3
                                                                                                                                             Lomonosov Moscow State University, Moscow, Russia
                                letters 2005; 95.1: 010503.
                                                                                                                                           Spontaneous parametric down-conversion (SPDC)             The new source can be optimized by passing to
                                                                                                                                           is a convenient source of entangled photons. Due          materials with even higher nonlinearity: for ex-      Dr Maria Chekhova
                                                                                                                                           to its relatively low efficiency, up to now it has only   ample, GaAs or other semiconductors. The thick-       Max-Planck Institute
                                                                                                                                           been used under the condition of phase matching.          ness of the material can then be reduced to the       for the Science of Light, Erlangen;

                                                                                                                                           In this case, the momentum of the pump photon             nanoscale, without a large reduction in the rate of   University of Erlangen-Nürnberg;
                                                                                                                                           is conserved by the daughter entangled photons.           coincidences. Further developments can be inte-       Lomonosov Moscow State
                                                                                                                                                                                                                                                           University
                                                                                                                                           At the same time, the necessity to satisfy the phase      gration into optical chips and nanostructuring of
                                                                                                                                           matching restricts the choice of available nonlin-        the nonlinear material.
                                                                                                                                           ear materials.                                            [1] Okoth C, Cavanna A, Santiago-Cruz T, and
                                                                                                                                           In this work, by using a 6.8 micrometre layer of              Chekhova M, Microscale generation of en-
                                                                                                                                           lithium niobate crystal in the geometry where its             tangled photons without momentum conser-
                                                                                                                                           strongest nonlinear tensor component was fully                vation. arXiv:1902.11218v2 [quant-ph].
                                                                                                                                           used, we observed SPDC without phase matching.            [2] Liscidini M. and Sipe J. Stimulated emis-
                                                                                                                                           The longitudinal momentum conservation could                  sion tomography. Phys. Rev. Lett. 2013; 111:
                                                                                                                                           be relaxed due to the small thickness of the non-             193602.
                                                                                                                                           linear layer. Under pumping with 170 mW of con-
                                                                                                                                           tinuous-wave radiation at 500 nm, we have regis-
                                                                                                                                           tered about 1 kHz flux of photon pairs collected
                                                                                                                                           into single-mode fibre [1].

                            Terahertz Radiation Induced Edge                                                                               The new SPDC source has extremely broad wave-
                                                                                                                                           length and angular spectra (about an octave in
                            Currents in Graphene                                                                                           wavelength and about 30° in angle). This broad
                                                                                                                                           spectrum is a result of the relaxed longitudinal
                            in the Quantum Hall Regime                                                                                     momentum conservation. Meanwhile, transverse
                                                                                                                                           momentum and energy are strictly conserved,
                            S. Candussio1, H. Plank1, M.V. Durnev2, J. Pernul1, K.M. Dantscher1, E. Mönch1, A. Sandner1,                   which leads to tight correlations of photons in
                            J. Eroms1, D. Weiss1, S. A. Tarasenko2, S. D. Ganichev1                                                        angle/space and frequency/time. This, in its turn,
                            1
                              University of Regensburg, Terahertz Centre, Regensburg, 93040, Germany                                       leads to an extremely high continuous-variable
                            2
                              Ioffe Institute, St. Petersburg, 194021, Russia                                                              entanglement of the produced two-photon state.
Susanne Candussio
                                                                                                                                           In a series of experiments, we have demonstrat-
University of Regensburg,   We report on the observation of terahertz (THz)        The used radiation has photon energies smaller
                                                                                                                                           ed a high rate of entangled pairs, a spectrum 200
Terahertz Centre            radiation induced chiral edge currents in graphene     than the cyclotron gap, and therefore, induces in-      nm broad, limited only by the bandwidth of the
                            in the quantum Hall regime (QHE) [1]. In this          direct transitions within the chiral edge channel.      equipment used, and a high degree of frequency
                            regime the direction of the edge photocurrent is       We demonstrate that the edge current is generated       and angular entanglement. The latter was tested
                            dictated by the polarity of the external magnetic      by Drude-like transitions within this channels re-      through stimulated-emission tomography (SET)
                            field while its magnitude depends on the radiation     sulting in a net velocity of the charge carriers. The   [2]. In one of the experiments, angular-space SET
                            polarization. Importantly, the current flows in the    developed microscopic theory describes well the         was performed, to the best of our knowledge for
                            same direction for electrons and holes, as con-        experimental data.                                      the first time.
                            firmed by experiments with variation of back gate
                            voltage. The overall behaviour of the edge photo-      [1] H. Plank, S.D. Ganichev et. al., 2D Mat. 6,
                            current, therefore, is qualitatively different from        011002 (2019)
                            the edge photocurrent excited at zero magnetic         [2] M. M. Glazov and S.D. Ganichev, Phys. Rep.
                            field [2,3] where the current direction is opposite        535, 101249 (2014)
                            for electron and holes and can be changed by var-      [3] J. Karch, S.D. Ganichev et. al., Phys. Rev. Lett.
                            iation of the radiation polarization.                      107, 276601 (2011)

12                                                                                                                                                                                                                                                                                      13
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                                 PARTICIPANTS

                                  Photoinduced Edge Current in Systems                                                                            Realizing 3D Random Walks
                                  with Two-Dimensional Electron Gas                                                                               of Correlated Photon Pairs
                                  Two-dimensional (2D) crystalline materials have        nation of the edge of 2D crystal with electro-mag-       Max Ehrhardt1, Robert Keil2, Matthias Heinrich1, Alexander Szameit1
                                  been in focus of scientific research since the dis-    netic wave. Such photoinduced edge current was
                                                                                                                                                  1
                                                                                                                                                    Univerity of Rostock, Institute for Physics, Albert-Einstein-Str. 23, 18059 Rostock, Germany
                                  covery of graphene monolayers [1]. Since then the      observed in graphene in [6], however the detailed
                                                                                                                                                  2
                                                                                                                                                    University of Innsbruck, Department of Experimental Physics, Technikerstr. 25d,
                                  class of 2D materials has significantly expanded       microscopic theory has not yet been developed.             6020 Innsbruck, Austria
                                  and now includes monolayers of transition metal        I will discuss possible mechanisms of the pho-
                                                                                                                                                  Quantum Walks (QWs) provide a bright field of                 Y. Lahini, N. Ismail, K. Wörhoff, Y. Bromb-
Dr Mikhail Durnev                 dichalcogenides [2], hexagonal boron nitride [3],      tocurrent generation in classical and quantum                                                                                                                            Max Ehrhardt
                                                                                                                                                  application from modelling quantum processes to               erg, Y. Silberberg, M. G. Thompson, and J. L.
Ioffe Institute, St. Petersburg   layered semiconductors, such as GaSe, GaTe [4],        regimes, the role of edge properties and external                                                                                                                        Univerity of Rostock,
                                                                                                                                                  quantum search algorithms and quantum com-                    O’Brien, “Quantum Walks of Correlated Pho-
                                  and many more. One can even combine those              magnetic field directed perpendicularly to the lay-                                                                                                                      Institute for Physics
                                                                                                                                                  putation. In order to study quantum interference,             tons,” Science 329(1500), 1500-1503 (2010).
                                  2D layers in stacks forming the so-called van der      er. I will present results of theoretical calculations
                                                                                                                                                  quantum walks for indistinguishable photon pairs        [2]   R. Keil, A. Szameit, F. Dreisow, M. Heinrich,
                                  Waals heterostructures [5]. The position of Fermi      and compare it to recent experiments.
                                                                                                                                                  have been implemented in one- and two-dimen-                  S. Nolte, and A. Tunnermann, "Photon corre-
                                  level in 2D materials can be controlled in experi-     [1] A. H. Castro Neto, F. Guinea, N. M. R. Peres,        sional waveguide lattices [1,2]. Two-dimensional              lations in two-dimensional waveguide arrays
                                  ment by changing the voltage on a gate electrode.            K. S. Novoselov, and A. K. Geim. The elec-         quantum walks have demonstrated features that                 and their classical estimate," Phys. Rev. A 81,
                                  In the case when Fermi level lies in the conduction          tronic properties of graphene. Rev Mod Phys        cannot be achieved in planar lattices [3]. Taking             023834 (2010).
                                  (or valence) band, the 2D gas of free charge carri-          2009; 81: 109.                                     this feature as motivation, our aim is to promote       [3]   K. Poulios, R. Keil, D. Fry, J. D. A. Meinecke,
                                  ers (electrons or holes) is formed within the layer.         Gang Wang, Alexey Chernikov, Mikhail M.
                                                                                         [2]                                                      the understanding of QWs for correlated photons               J. C. F. Matthews, A. Politi, M. Lobino, M.
                                  This gas controls electronic, optical and thermal            Glazov, Tony F. Heinz, Xavier Marie, Thierry       on three-dimensional lattices with the vision to              Gräfe, M. Heinrich, S. Nolte, A. Szameit,
                                  properties of the system and thus its study is of            Amand, and Bernhard Urbaszek. Colloqui-            establish a basis for new, on-chip quantum simu-              and J. L. O’Brien, “Quantum Walks of Cor-
                                  importance for both fundamental and applied sci-             um: Excitons in atomically thin transition         lation and computing applications.                            related Photon Pairs in Two-Dimensional
                                  ence. In this talk, I will present theoretical study         metal dichalcogenides. Rev Mod Phys 2018;
                                                                                                                                                  The direct femtosecond laser-writing technique                Waveguide Arrays,” Phys. Rev. Lett. 112,
                                  of an optoelectronic phenomenon, namely, the                 90: 021001
                                                                                                                                                  is a promising route to nearest neighbor-coupled              143604 (2014).
                                  emergence of direct electric current upon illumi-            G Cassabois, P Valvin, B Gil. Hexagonal bo-
                                                                                         [3]
                                                                                                                                                  geometries of waveguides for QWs in one and two         [4]   K. M. Davis, K. Miura, N. Sugimoto, and
                                                                                               ron nitride is an indirect bandgap semicon-                                                                      K. Hirao, “Writing waveguides in glass with
                                                                                                                                                  dimensions [4]. This writing technique creates bi-
                                                                                               ductor. Nat Phot 2016; 10: 262.                                                                                  a femtosecond laser,” Opt. Lett. 21(21), 1729
                                                                                                                                                  refringent waveguide [5] with a controllable opti-
                                                                                         [4]   V. Tayari, B. V. Senkovskiy, D. Rybkovskiy,                                                                      (1996).
                                                                                                                                                  cal axis orientation [6,7]. Hence, direct laser-writ-
                                                                                               N. Ehlen, A. Fedorov, C.-Y. Chen, J. Avila,                                                                [5]   P. Yang, G. R. Burns, J. Guo, T. S. Luk, and G.
                                                                                                                                                  ten waveguides provide a full polarization control.
                                                                                               M. Asensio, A. Perucchi, P. di Pietro, L. Yas-                                                                   A. Vawter, “Femtosecond laser-pulse-induced
                                                                                               hina, I. Fakih, N. Hemsworth, M. Petres-           In our work, we show the equivalence of cou-                  birefringence in optically isotropic glass,”
                                                                                               cu, G. Gervais, A. Grüneis, and T. Szkopek.        pling behavior between two waveguides and or-                 J. Appl. Phys. 95(10), 5280–5283 (2004).
                                                                                               Quasi-two-dimensional thermoelectricity in         thogonal polarization direction in a birefringent       [6]   R. Heilmann, M. Gräfe, S. Nolte, and A. Sza­
                                                                                               SnSe. Phys Rev B 2018; 97: 045424.                 waveguide. We use the polarization and its afore              meit, “Arbitrary photonic wave plate opera-
                                                                                         [5]   A. K. Geim, I. V. Grigorieva. Van der Waals        mentioned features to extend a two-dimension-                 tions on chip: realizing hadamard, pauli-x,
                                                                                               heterostructures. Nature 2013; 499: 419.           al waveguide lattice by the third dimension. We               and rotation gates for polarisation qubits,”
                                                                                         [6]   J. Karch, C. Drexler, P. Olbrich, M. Fehren-       observe correlations of photon pairs unveiling                Sci. Rep. 4(1), 4118 (2014).
                                                                                               bacher, M. Hirmer, M. M. Glazov, S. A. Ta­         Hong-Ou-Mandel interference as well as phe-             [7]   C.-Y. Wang, J. Gao, and X.-M. Jin, “On-chip
                                                                                               rasenko, E. L. Ivchenko, B. Birkner, J. Eroms,     nomena unique to these structures.                            rotated polarization directional coupler fab-
                                                                                               D. Weiss, R. Yakimova, S. Lara-Avila, S. Ku­       [1] A. Peruzzo, M. Lobino, J. C. F. Matthews,                 ricated by femtosecond laser direct writing,”
                                                                                               batkin, M. Ostler, T. Seyller, and S. D. Ga­           N. Ma­tsuda, A. Politi, K. Poulios, X.-Q. Zhou,           Opt. Lett. 44(1), 102–105 (2019).
                                                                                               ni­chev. Terahertz Radiation Driven Chiral
                                                                                               Edge Currents in Graphene. Phys Rev Lett
                                                                                               2011; 107: 276601.

14                                                                                                                                                                                                                                                                                        15
9th WEEK OF THE YOUNG RESEARCHER - QUANTUM SCIENCE: LIGHT-MATTER INTERACTION
QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                               PARTICIPANTS

                                 Towards Spontaneous Parametric                                                                                  Nonlinear and Tunable All-Dielectric
                                 Down-Conversion in Lithium Niobate                                                                              Metasurfaces
                                 Metasurfaces                                                                                                    The use of the optically induced Mie resonances         tures involving light localization in electric and
                                                                                                                                                 in all-dielectric nanostructures – metasurfaces al-     magnetic dipolar resonances. Special attention is
                                 Anna Fedotova1, Mohammadreza Younesi1, Jürgen Sautter1, Michael Steinert1, Reinhard Geiss1,
                                                                                                                                                 lows us to reveal new physical effects which can        addressed to nanoparticle oligomers consisting of
                                 Thomas Pertsch1,2, Frank Setzpfandt1, Isabelle Staude1
                                                                                                                                                 be used in many prospective applications from           several, up to four, nanoparticles having collec-
                                 1
                                   Institute of Applied Physics, Abbe Centre of Photonics, Albert-Einstein-Straße 15,
                                                                                                                                                 tunable antennas and flat optical devices to ul-        tive resonances. Then, we discuss ultrafast tuna-
                                   07745 Jena, Germany
Anna Fedotova                                                                                                                                    tra-sensitive sensors and active nanophotonic           bility and all-optical switching in subwavelength      Professor Dr Andrey Fedyanin
                                 2
                                   Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Straße 7,
Institute of Applied Physics,                                                                                                                    components. In this talk, we discuss various opti-      nonlinear dielectric nanostructures exhibiting lo-     Faculty of Physics,
                                   07745 Jena, Germany
Abbe Centre of Photonics, Jena                                                                                                                   cal effects in all-dielectric structures composed of    calized magnetic Mie resonances. The results are       Lomonosov Moscow State
                                 Lithium niobate (LN), a birefringent crystal, is an     in transmission, which demonstrated strong SHG          Mie resonant nanoparticles upon their interaction       compared with optical switching based on Bloch         University

                                 attractive material for nonlinear photonics due to      signal when exciting at 1550 nm with a pulsed la-       with femtosecond laser pulses. We consider non-         surface waves and optical Tamm states in one-di-
                                 its wide transparency range and high second-or-         ser. At the back-focal plane of the collecting objec-   linear-optical effects based on quadratic and cubic     mensional photonic crystals, and creation of a new
                                 der nonlinearity. Among other applications, it has      tive, the 0th and 1st diffraction orders can be seen    nonlinearities of resonant dielectric nanostruc-        low-loss active nanophotonic devices is discussed.
                                 been used for fabrication of fast optical modula-       corresponding to the period of the metasurface.
                                 tors and nonlinear frequency converters. Howev-         With these results, we show that resonant metas-
                                 er, almost all implementations to date were using       urface based on lithium niobate is a suitable plat-
                                 bulk LN crystals or waveguides. Although isolated
                                 Mie-type nanoresonators in lithium niobate have
                                                                                         form for second-harmonic generation. Due to the         Multimode Four-Photon
                                                                                         principle of quantum-classical correspondence,
                                 been shown very recently [1], functional metasur-       one can expect efficient spontaneous parametric         Hong-Ou-Mandel Interference
                                 faces [2,3] based on densely packed arrangements        down-conversion from this sample. Therefore, our
                                 of such nanoresonators have not yet been demon-         next goal is studying the quantum behavior of the       Alessandro Ferreri1, Vahid Ansari1, Benjamin Brecht1, Christine Silberhorn1, Polina R. Sharapova1
                                 strated. The key feature of these metasurfaces, the     fabricated metasurfaces.                                1
                                                                                                                                                   Integrated Quantum Optics, Paderborn University, Warbugerstr. 100,
                                 resonant enhancement of local fields, may allow                                                                   33098 Paderborn, Germany
                                                                                         [1] Timpu, F., Sendra, J., Renaut, C., Lang, L.,
                                 to boost nonlinear effects such as second-har-
                                                                                             Timofeeva, M., Buscaglia, M.T., Buscaglia,
                                 monic generation and spontaneous parametric                                                                     The conventional two-photon Hong-Ou-Mandel              the number of Schmidt modes and the antibunch-
                                                                                             V. and Grange, R., 2019. Lithium Niobate
                                 down-conversion (SPDC), thus offering interest-                                                                 (HOM) interference plays an important role in           ing behaviour is confirmed by using the chirped
                                                                                             Nanocubes as Linear and Nonlinear Ultra-                                                                                                                           Alessandro Ferreri
                                 ing opportunities for the efficient generation of                                                               testifying the degree of indistinguishability of        pump pulse [3]. By fixing the spectral width and
                                                                                             violet Mie Resonators. ACS Photonics, 6(2),                                                                                                                        Integrated Quantum Optics,
                                 pairs of entangled photons.                                                                                     photons. Recently, multiphoton quantum inter-           varying the spectral quadratic phase (chirp) of the
                                                                                             pp. 545–552.                                                                                                                                                       Paderborn University
                                                                                                                                                 ference is in focus of research since it is a crucial   pump laser, the PDC state with the chirped pulse
                                 In this work, we have designed, fabricated and ex-      [2] Löchner, F.J., Fedotova, A.N., Liu, S., Keeler,
                                                                                                                                                 ingredient of boson samplings and a promising           is characterized by the same signal-idler spectrum
                                 perimentally investigated nonlinear metasurfaces            G.A., Peake, G.M., Saravi, S., Shcherbakov,
                                                                                                                                                 tool for a high dimensional entanglement [1].           as in the single-mode regime but completely dif-
                                 consisting of an array of LN nanocubes featuring            M.R., Burger, S., Fedyanin, A.A., Brener, I.
                                                                                                                                                 In this research we investigate both theoreti-          ferent mode structure.
                                 Mie-type resonances at the telecom wavelengths.             and Pertsch, T., 2018. Polarization-depend-
                                                                                                                                                 cally and experimentally the properties of the          In conclusion, it was shown that it is possible to
                                 Prior to performing quantum experiments, we                 ent second harmonic diffraction from reso-
                                                                                                                                                 four-photon HOM interference.                           control the interference pattern, coherent length of
                                 characterized second-harmonic generation (SHG)              nant gaas metasurfaces. ACS Photonics, 5(5),
                                 from the metasurfaces. Firstly, in the optical trans-       pp. 1786–1793.                                      We consider four photons generated in the type-         photons and bunching properties of the four-pho-
                                 mittance spectra, we observed electric dipole and       [3] Decker, M., Staude, I., Falkner, M., Do­min­        II PDC process in a KTP waveguide. Dispersion           ton HOM interference by modifying the number
                                 magnetic dipole Mie-type resonances in the vi-              guez, J., Neshev, D.N., Brener, I., Pertsch, T.     properties of KTP allow engineering a single            of Schmidt modes.
                                 cinity of a target wavelength 1550 nm. Numerical            and Kivshar, Y.S., 2015. High‐efficiency die-       Schmidt mode source as well as a multimode              [1] Y.-S. Ra, M.C. Tichy, H.-T. Lim, O. Kwon,
                                 simulations confirmed the nature of resonanc-               lectric Huygens’ surfaces. Advanced Optical         source by changing the pulse duration or by                 F. Mintert, A. Buchleitner, Y.-H. Kim, Non-
                                 es. Secondly, we carried out SHG measurements               Materials, 3(6), pp. 813–820.                       chirping the pump pulse [2]. The type-II PDC                monotonic quantum-to-classical transition
                                                                                                                                                 source creates two photon pairs having two or-              in multiparticle interference, Proceedings of
                                                                                                                                                 thogonal polarization which were split up in two            the National Academy of Sciences, 110,1227-
                                                                                                                                                 arms of an interferometer by a polarization beam            1231 (2013)
                                                                                                                                                 splitter. By making them have the same polariza-        [2] G. Harder, V. Ansari, B. Brecht, T. Dirmeier,
                                                                                                                                                 tion, we let them interfere on a beam splitter and          C. Marquardt, and C. Silberhorn, Optics ex-
                                                                                                                                                 finally they were detected.                                 press 21, 13975 (2013).
                                                                                                                                                 The theoretical simulations and the experimen-          [3] V. Ansari, J. M. Donohue, M. Allgaier, L. San-
                                                                                                                                                 tal results coincide and show that via increasing           soni, B. Brecht, J. Roslund, N. Treps, G. Hard-
                                                                                                                                                 the number of Schmidt modes, an antibunching                er, and C. Silberhorn, Physical review letters
                                                                                                                                                 peak appears. Furthermore, the relation between             120, 213601 (2018).

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QUANTUM SCIENCE: LIGHT-MATTER INTERACTION                                                                                                                                                                                                                                            PARTICIPANTS

                                   Plasmon-Assisted Ultrafast                                                                                     Light Scattering by Lattices of Resonant
                                   Photodynamics in Quantum Dots                                                                                  Nanoparticles in Dipole Approximation
                                   A.M. Flatae1, F. Tantussi2, G.C. Messina2, F. De Angelis2, and M. Agio1,3                                      Ilia Fradkin1,2, Sergey Dyakov1, Nikolay Gippius1
                                   1
                                     University of Siegen, Laboratory of Nano-Optics and Cµ, Siegen, 57072, Germany                               1
                                                                                                                                                    Skolkovo Institute of Science and Technology, Nobel Street 3, Moscow 143025, Russia
                                   2
                                     Istituto Italiano di Tecnologia, Genova, 16163, Italy                                                        2
                                                                                                                                                    Moscow Institute of Physics and Technology, Institutskiy pereulok 9,
                                   3
                                     National Institute of Optics (INO-CNR), Florence, 50125, Italy                                                 Moscow Region 141701, Russia

                                   Colloidal quantum dots (QDs) represent a prom-         of magnitude. Increasing the quantum efficiency         Rigorous coupled-wave analysis (RCWA) is a very                We demonstrate the performance of the proposed
Assegid M. Flatae                  ising nanoscale material for application in opto-      of the excitonic transitions turns the defect-rich      effective tool for studying optical properties of              method by considering plasmonic lattices embed-             Ilia Fradkin
University of Siegen,              electronics, photovoltaics and in the life sciences.   bare QD into a bright photon source, with impli-        multilayered vertically invariant periodic struc-              ded in a homogeneous ambiance and placed inside             Skolkovo Institute of Science
Laboratory of Nano-Optics and Cµ   Limitations like fluorescence blinking, Auger pro-     cations for nanoscale lasers, light emitting devices,                                                                  and onto optical waveguides, and compare our re-            and Technology, Moscow;
                                                                                                                                                  tures. However, it fails to deal with arrays of small
                                   cess and surface traps are commonly addressed by       solar cells and ultrafast single-photon sources. The                                                                   sults with experimental papers. Such phenomena              Moscow Institute of Physics
                                                                                                                                                  particles because of high gradients in a local field.
                                                                                                                                                                                                                                                                             and Technology
                                   growing a wide-bandgap shell. However, the shell       approach can also be used to shape the emission         In our paper [1], we implement discrete dipole                 as localized surface plasmon resonances (LSPRs)
                                   isolates the excitonic wave function and reduces       spectrum and for achieving strong coupling at           approximation (DDA) for the construction of                    and lattice plasmon resonances (LPRs) are ob-
                                   its interaction with the external environment nec-     room temperature.                                       scattering matrices of arrays of resonant nanopar-             served as well as their hybridization with photonic
                                   essary for different applications. In addition, the    [1] Flatae AM, Tantussi F, Messina GC, Moham-           ticles. This strongly speeds up the calculations and           guided modes. High accuracy and fast conver-
                                   long fluorescence lifetime hinders their applica-          madi A, De Angelis F, Agio M. Plasmon-              therefore provides an opportunity for thorough                 gence of our approach are shown by a comparison
                                   tion in high-speed optoelectronics.                        ic gold nanocones in the near-infrared for          consideration of various layered structures with               with other computational approaches. Typical lim-
                                   We demonstrate a high degree of control on the             quantum nano-optics. Adv. Opt. Mater. 2017;         small periodic inclusions in terms of the RCWA.                its of applicability of our approximate method are
                                   emission dynamics of a bare core CdTe quantum              5: 1700586.                                         We study in detail three main stages of the meth-              determined by an exploration of the dependence of
                                   dot by plasmon coupling to gold nanocones. We          [2] Flatae AM, Tantussi F, Messina GC, De An-           od: calculation of polarizability tensor of a single           its error on the parameters of the structure.
                                   show that surface defect state emission and Au-            gelis F, Agio M. Plasmon-assisted suppression       nanoparticle, effective polarizability of this parti-          [1] Fradkin IM, Dyakov SA, and Gippius NA
                                   ger processes from a trap-rich quantum dot can             of Surface trap states and enhanced band-           cle in a lattice and corresponding scattering ma-                   Fourier modal method for the description of
                                   be significantly quenched by enhancing the band-           edge emission in a bare CdTe Quantum dot.           trix of the layer for further integration in the con-               nanoparticle lattices in the dipole approxima-
                                   edge state emission rate by more than three orders         J. Phys. Chem. Lett. 2019; 10: 2874-2878.           ventional RCWA approach.                                            tion Phys. Rev. B 2019; 99: 075310

                                                                                                                                                  Fig. 1. Extinction of the gold nanoparticle lattice in bulk silica for a normally incident light calculated by different
                                                                                                                                                  methods as a function of total number of Fourier harmonics. The proposed approach (1) converges even faster than
                                                                                                                                                  conventional Fourier modal method enhanced by adaptive spatial resolution (RCWA-ASR) and provides precise results.

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