SKM 2021 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 15: Focus Session: Tailored Nonlinear Photonics
HL 15.1: Invited Talk
Thursday, September 30, 2021, 10:00–10:30, H4
Quasi-instantaneous switch-off of deep-strong light-matter coupling — •Christoph Lange1, Joshua Mornhinweg2, Maike Halbhuber2, Viola Zeller2, Cristiano Ciuti3, Dominique Bougeard2, and Rupert Huber2 — 1Department of Physics, TU Dortmund University, 44227 Dortmund, Germany — 2Department of Physics, University of Regensburg, 93040 Regensburg, Germany — 3Université de Paris, laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
Optical microresonators facilitate custom-tailored quantum states of matter by dressing electronic excitations with virtual cavity photons. Once the rate of energy exchange between light and matter modes exceeds the carrier frequency of light, "deep-strong coupling" emerges, which profoundly modifies the vacuum ground state and gives rise to novel phenomena including cavity-mediated superconductivity and other phase transitions. While the exploration of the equilibrium properties of deep-strong coupling has just started, yet more unusual effects are expected on subcycle scales. Here, we explore the dynamics that arises when deep-strong coupling is switched off abruptly. The experiments employ cyclotron resonances of two-dimensional electron gases coupled to light modes of custom-cut THz nanoresonators, which can be switched off by femtosecond photoexcitation. The polariton states are extinguished more than an order of magnitude faster than the polariton cycle duration, leading to sub-polariton-cycle oscillations as confirmed by a quantum model. Our experiments introduce time as a new control parameter for deep-strong light-matter coupling.