Technische Physik

    Dr. Simon Betzold

    Dr. Simon Betzold

    Group Leader
    Leader of the "Hybrid Polaritonics" group
    Technische Physik
    University of Würzburg
    Am Hubland
    97074 Würzburg
    Gebäude: P1 (Physik)
    Raum: E071
    Telefon: +49 931 31-85454

    ORCID: 0000-0001-9217-1832

    Researcher ID: AAC-5775-2020

    Google Scholar: Account

    The focus of the hybrid polaritonics group, led by Simon Betzold, is set on the investigation of light-matter coupled systems. Of particular interest are microcavities with integrated low dimensional materials, such as quantum wells, organic emitters or monolayer materials.


    High quality microcavities with embedded quantum wells allow for investigation of strong coupling between excitons and photons. This light-matter hybridization gives rise to new quasiparticles, the so-called exciton polaritons. Their energy momentum dispersion E(k) can be measured directly by angle resolved spectroscopy. Polaritons are bosons and can undergo a condensation process at rather high temperatures (up to ~ 100 K in GaAs). III-V semiconductors offer the unique possibility to excite these condensates not only optically but also electrically. Our current research interests include optimization of electrically driven polariton condesates, detailed studies of their coherence properties, and the fabrication of advanced polaritonic devices.

    Two-dimensional materials

    Transition metal dichalcogenides (TMDCs), such as MoS2, MoSe2 and WSe2 exhibit an indirect bandgap in bulk material, yet they become direct bandgap semiconductors in the monolayer limit. Simlilar to graphene, such atomic monolayers can be produced by simple exfoliation techniques. The unique combination of huge exciton binding energies, large Bohr radii and peculiar spinor properties explains the rising interest in this new class of semiconductors. In our group, we investigate the possibilities to exploit these properties for high temperature polaritonics.

    Organic photonics

    Our research focuses on the exploration and exploitation of the unique optical properties offered by organic semiconductors. We embed the organic materials in high-quality optical microcavities and investigate the interactions between organic excitons and the cavity field. On the one hand, organic solids can act as active gain material and may turn the system into the regime of stimulated emission. On the other hand, when suitable resonators are used, organic semiconductors enable the observation of strong light-matter interaction effects by serving as active exciton reservoir in the strongly coupled exciton-photon system. They provide a robust platform for the investigation of polariton physics at room temperature.

    Hybrid organic-inorganic systems

    We aim at demonstrating the room-temperature operation of an electrically driven polariton laser that combines the outstanding properties of both inorganic and organic semiconductors. Inorganic semiconductor microcavities are commonly used for polariton experiments as a consequence of the precise control that is achieved over nearly all material parameters with modern epitaxial deposition technologies. However, main issues such as room-temperature stability of the strong coupling regime as a result of exciton dissociation remain challenging. In contrast to that, organic semiconductors provide record high exciton stability due to a strong localization of particles but lack high charge carrier concentrations as well as processability and stability during sample fabrication. A combination of both inorganic and organic semiconductors as active layers would then comprise the room-temperature operation and high radiation efficiency of specific organics and the device-applicability of inorganics. This will enable new technologies in medical imaging and quantum communication.

    Polarized and Unpolarized Emission from a Single Emitter in a Bullseye Resonator
    G. Peniakov, Q. Buchinger, M. Helal, S. Betzold, Y. Reum, M. B. Rota, G. Ronco, M. Beccaceci, T. M. Krieger, S. F. C. Da Silva, A. Rastelli, R. Trotta, A. Pfenning, S. Höfling, and T. Huber-Loyola
    Laser & Photonics Reviews (2024), DOI: 10.1002/lpor.202300835

    Optical properties of circular Bragg gratings with labyrinth geometry to enable electrical contacts
    Q. Buchinger, S. Betzold, S. Höfling, and T. Huber-Loyola
    Appl. Phys. Lett. 122, 111110 (2023), DOI: 10.1063/5.0136715

    Electro-optical Switching of a Topological Polariton Laser
    P. Gagel, T. H. Harder, S. Betzold, O. A. Egorov, J. Beierlein, H. Suchomel, M. Emmerling, A. Wolf, U. Peschel, S. Höfling, C. Schneider, and S. Klembt
    ACS Photonics 9, 405 (2022), DOI: 10.1021/acsphotonics.1c01605

    Room-Temperature Topological Polariton Laser in an Organic Lattice
    M. Dusel, S. Betzold, T. H. Harder, M. Emmerling, J. Beierlein, J. Ohmer, U. Fischer, R. Thomale, C. Schneider, S. Höfling, and S. Klembt
    Nano Lett. 21, 6398 (2021), DOI: 10.1021/acs.nanolett.1c00661

    Purcell-Enhanced Single Photon Source Based on a Deterministically Placed WSe2 Monolayer Quantum Dot in a Circular Bragg Grating Cavity
    O. Iff, Q. Buchinger, M. Moczała-Dusanowska, M. Kamp, S. Betzold, M. Davanço, K. Srinivasan, S. Tongay, C. Antón-Solanas, S. Höfling, and C. Schneider
    Nano Lett. 21, 4715 (2021), DOI: 10.1021/acs.nanolett.1c00978

    Hyperspectral study of the coupling between trions in WSe 2 monolayers to a circular Bragg grating cavity
    O. Iff, M. Davanço, S. Betzold, M. Moczała-Dusanowska, M. Wurdack, M. Emmerling, S. Höfling, and C. Schneider
    C. R. Phys. 22, 1 (2021), DOI: 10.5802/crphys.76

    Coherence and Interaction in Confined Room-Temperature Polariton Condensates with Frenkel Excitons
    S. Betzold, M. Dusel, O. Kyriienko, C. P. Dietrich, S. Klembt, J. Ohmer, U. Fischer, I. A. Shelykh, C. Schneider, and S. Höfling
    ACS Photonics 7, 384 (2020), DOI: 10.1021/acsphotonics.9b01300

    Room temperature organic exciton-polariton condensate in a lattice
    M. Dusel, S. Betzold, O. A. Egorov, S. Klembt, J. Ohmer, U. Fischer, S. Höfling, and C. Schneider
    Nat. Commun. 11, 2863 (2020), DOI: 10.1038/s41467-020-16656-0

    Optomechanical tuning of the polarization properties of micropillar cavity systems with embedded quantum dots
    S. Gerhardt, M. Moczała-Dusanowska, Ł. Dusanowski, T. Huber, S. Betzold, J. Martín-Sánchez, R. Trotta, A. Predojević, S. Höfling, and C. Schneider
    Phys. Rev. B 101, 245308 (2020), DOI: 10.1103/PhysRevB.101.245308

    Spatio-temporal coherence in vertically emitting GaAs-based electrically driven polariton lasers
    H. Suchomel, M. Klaas, S. Betzold, P. Gagel, J. Beierlein, S. Klembt, C. Schneider, and S. Höfling
    Appl. Phys. Lett. 116, 171103 (2020), DOI: 10.1063/5.0007456

    Polarization-dependent light-matter coupling and highly indistinguishable resonant fluorescence photons from quantum dot-micropillar cavities with elliptical cross section
    S. Gerhardt, M. Deppisch, S. Betzold, T. H. Harder, T. C. H. Liew, A. Predojević, S. Höfling, and C. Schneider
    Phys. Rev. B 100, 115305 (2019), DOI: 10.1103/PhysRevB.100.115305

    Nonresonant spin selection methods and polarization control in exciton-polariton condensates
    M. Klaas, O. A. Egorov, T. C. H. Liew, A. V. Nalitov, V. Marković, H. Suchomel, T. H. Harder, S. Betzold, E. A. Ostrovskaya, A. V. Kavokin, S. Klembt, S. Höfling, and C. Schneider
    Phys. Rev. B 99, 115303 (2019), DOI: 10.1103/PhysRevB.99.115303

    Polariton-lasing in microcavities filled with fluorescent proteins
    S. Betzold, C. P. Dietrich, M. Dusel, M. Emmerling, L. Tropf, M. Schubert, N. M. Kronenberg, J. Ohmer, U. Fischer, M. C. Gather, and S. Höfling
    Proc. SPIE, Quantum Sensing and Nano Electronics and Photonics XV, 66 (2018), DOI: 10.1117/12.2292045

    Tunable Light–Matter Hybridization in Open Organic Microcavities
    S. Betzold, S. Herbst, A. A. P. Trichet, J. M. Smith, F. Würthner, S. Höfling, and C. P. Dietrich
    ACS Photonics 5, 90 (2018), DOI: 10.1021/acsphotonics.7b00552

    Intrinsic and environmental effects on the interference properties of a high-performance quantum dot single-photon source
    S. Gerhardt, J. Iles-Smith, D. P. S. McCutcheon, Y.-M. He, S. Unsleber, S. Betzold, N. Gregersen, J. Mørk, S. Höfling, and C. Schneider
    Phys. Rev. B 97, 195432 (2018), DOI: 10.1103/PhysRevB.97.195432

    Deterministic coupling of quantum emitters in WSe2 monolayers to plasmonic nanocavities
    O. Iff, N. Lundt, S. Betzold, L. N. Tripathi, M. Emmerling, S. Tongay, Y. J. Lee, S.-H. Kwon, S. Höfling, and C. Schneider
    Opt. Express 26, 25944 (2018), DOI: 10.1364/OE.26.025944

    Spontaneous Emission Enhancement in Strain-Induced WSe 2 Monolayer-Based Quantum Light Sources on Metallic Surfaces
    L. N. Tripathi, O. Iff, S. Betzold, Ł. Dusanowski, M. Emmerling, K. Moon, Y. J. Lee, S.-H. Kwon, S. Höfling, and C. Schneider
    ACS Photonics 5, 1919 (2018), DOI: 10.1021/acsphotonics.7b01053

    Observation of bosonic condensation in a hybrid monolayer MoSe2-GaAs microcavity
    M. Waldherr, N. Lundt, M. Klaas, S. Betzold, M. Wurdack, V. Baumann, E. Estrecho, A. V. Nalitov, E. Cherotchenko, H. Cai, E. A. Ostrovskaya, A. V. Kavokin, S. Tongay, S. Klembt, S. Höfling, and C. Schneider
    Nat. Commun. 9, 3286 (2018), DOI: 10.1038/s41467-018-05532-7

    Exciton dynamics in solid-state green fluorescent protein
    C. P. Dietrich, M. Siegert, S. Betzold, J. Ohmer, U. Fischer, and S. Höfling
    Appl. Phys. Lett. 110, 43703 (2017), DOI: 10.1063/1.4974033

    Three-dimensional photonic confinement in imprinted liquid crystalline pillar microcavities
    M. Dusel, S. Betzold, S. Brodbeck, S. Herbst, F. Würthner, D. Friedrich, B. Hecht, S. Höfling, and C. P. Dietrich
    Appl. Phys. Lett. 110, 201113 (2017), DOI: 10.1063/1.4983565

    Valley polarized relaxation and upconversion luminescence from Tamm-plasmon trion–polaritons with a MoSe 2 monolayer
    N. Lundt, P. Nagler, A. V. Nalitov, S. Klembt, M. Wurdack, S. Stoll, T. H. Harder, S. Betzold, V. Baumann, A. V. Kavokin, C. Schüller, T. Korn, S. Höfling, and C. Schneider
    2d Mater. 4, 25096 (2017), DOI: 10.1088/2053-1583/aa6ef2

    Observation of macroscopic valley-polarized monolayer exciton-polaritons at room temperature
    N. Lundt, S. Stoll, P. Nagler, A. V. Nalitov, S. Klembt, S. Betzold, J. Goddard, E. Frieling, A. V. Kavokin, C. Schüller, T. Korn, S. Höfling, and C. Schneider
    Phys. Rev. B 96 (2017), DOI: 10.1103/PhysRevB.96.241403

    Room temperature strong coupling in a semiconductor microcavity with embedded AlGaAs quantum wells designed for polariton lasing
    H. Suchomel, S. Kreutzer, M. Jörg, S. Brodbeck, M. Pieczarka, S. Betzold, C. P. Dietrich, G. Sęk, C. Schneider, and S. Höfling
    Opt. Express 25, 24816 (2017), DOI: 10.1364/OE.25.024816

    Impact of exsitu rapid thermal annealing on magneto-optical properties and oscillator strength of In(Ga)As quantum dots
    T. Braun, S. Betzold, N. Lundt, M. Kamp, S. Höfling, and C. Schneider
    Phys. Rev. B 93, 155307 (2016), DOI: 10.1103/PhysRevB.93.155307

    Room-temperature Tamm-plasmon exciton-polaritons with a WSe2 monolayer
    N. Lundt, S. Klembt, E. Cherotchenko, S. Betzold, O. Iff, A. V. Nalitov, M. Klaas, C. P. Dietrich, A. V. Kavokin, S. Höfling, and C. Schneider
    Nat. Commun. 7, 13328 (2016), DOI: 10.1038/ncomms13328