Spatial coherence of room-temperature monolayer WSe2 exciton-polaritons in a trap

Hangyong Shan; Lukas Lackner; Bo Han; Evgeny Sedov; Christoph Rupprecht; Heiko Knopf; Falk Eilenberger; Johannes Beierlein; Nils Kunte; Martin Esmann; Kentaro Yumigeta; Kenji Watanabe; Takashi Taniguchi; Sebastian Klembt; Sven Höfling; Alexey V Kavokin; Sefaattin Tongay; Christian Schneider; Carlos Antón-Solanas

doi:10.1038/s41467-021-26715-9

Spatial coherence of room-temperature monolayer WSe₂ exciton-polaritons in a trap

Nat Commun. 2021 Nov 4;12(1):6406. doi: 10.1038/s41467-021-26715-9.

Authors

Hangyong Shan¹, Lukas Lackner², Bo Han², Evgeny Sedov^{3

4

5}, Christoph Rupprecht⁶, Heiko Knopf^{7

8

9}, Falk Eilenberger^{7

8

9}, Johannes Beierlein⁶, Nils Kunte², Martin Esmann², Kentaro Yumigeta¹⁰, Kenji Watanabe¹¹, Takashi Taniguchi¹², Sebastian Klembt⁶, Sven Höfling⁶, Alexey V Kavokin^{3

4

13}, Sefaattin Tongay¹⁴, Christian Schneider¹⁵, Carlos Antón-Solanas¹⁶

Affiliations

¹ Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany. hangyong.shan@uni-oldenburg.de.
² Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany.
³ Key Laboratory for Quantum Materials of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.
⁴ Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.
⁵ Vladimir State University named after A. G. and N. G. Stoletovs, Gorky str. 87, 600000, Vladimir, Russia.
⁶ Technische Physik, Universität Würzburg, D-97074, Würzburg, Am Hubland, Germany.
⁷ Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University, 07745, Jena, Germany.
⁸ Fraunhofer-Institute for Applied Optics and Precision Engineering IOF, 07745, Jena, Germany.
⁹ Max Planck School of Photonics, 07745, Jena, Germany.
¹⁰ School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona, 85287, USA.
¹¹ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
¹² International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
¹³ Physics and Astronomy, University of Southampton, Highfield, SO171BJ, Southampton, United Kingdom.
¹⁴ School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona, 85287, USA. sefaattin.tongay@asu.edu.
¹⁵ Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany. christian.schneider@uni-oldenburg.de.
¹⁶ Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany. carlos.anton-solanas@uni-oldenburg.de.

Abstract

The emergence of spatial and temporal coherence of light emitted from solid-state systems is a fundamental phenomenon intrinsically aligned with the control of light-matter coupling. It is canonical for laser oscillation, emerges in the superradiance of collective emitters, and has been investigated in bosonic condensates of thermalized light, as well as exciton-polaritons. Our room temperature experiments show the strong light-matter coupling between microcavity photons and excitons in atomically thin WSe₂. We evidence the density-dependent expansion of spatial and temporal coherence of the emitted light from the spatially confined system ground-state, which is accompanied by a threshold-like response of the emitted light intensity. Additionally, valley-physics is manifested in the presence of an external magnetic field, which allows us to manipulate K and K' polaritons via the valley-Zeeman-effect. Our findings validate the potential of atomically thin crystals as versatile components of coherent light-sources, and in valleytronic applications at room temperature.