Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 40: THz and MIR Physics in Semiconductors
HL 40.5: Invited Talk
Friday, September 9, 2022, 10:45–11:15, H33
Ultrafast subcycle dynamics of deep-strong light-matter coupling — •Joshua Mornhinweg1, Maike Halbhuber1, Laura Diebel1, Viola Zeller1, Josef Riepl1, Cristiano Ciuti2, Dominique Bougeard1, Rupert Huber2, and Christoph Lange3 — 1Universität Regensburg, Germany — 2Université de Paris, France — 3TU Dortmund, Germany
Subcycle interactions of strong light fields and electric charges lead to multi-octave spanning dynamics such as high-harmonic generation. In optical microcavities, even vacuum field fluctuations can drive non-perturbative light-matter coupling. Once the rate of energy exchange between the cavity and the matter mode becomes of the order of the carrier frequency of light, ultrastrong coupling (USC) emerges, and the profound modification of the vacuum ground state gives rise to novel phenomena such as cavity-mediated superconductivity. Here, we explore intriguing subcycle effects of USC including non-adiabatic dynamics occurring during quasi-instantaneous switch-off of the coupling, for which we observe sub-polariton-cycle polarization oscillations. Additionally, we drive USC with strong coherent THz fields to reveal nonlinear interactions between the polariton states, breaking the normal-mode approximation. Finally, we present deep-strong coupling (DSC) of multiple light and matter modes, creating a spectrum of Landau magneto-polaritons which covers 6 optical octaves, a coupling strength of ΩR/ωc ≈ 3.0, and a record virtual ground state population exceeding 1 photon. Our results open up new avenues for dynamically tailoring of USC and DSC on strongly subcycle timescales.