The strong light-matter interaction in a photonic cavity is a very important testbed for the understanding of fundamental quantum electrodynamics. When the light-matter interaction enters the ultrastrong coupling regime, exotic quantum phenomena emerge, of which the most prominent one is the Bloch-Siegert frequency shift indicative of the breakdown of the rotating wave approximation [1]. Intriguing virtual excitations and coupling mechanisms have been discovered as a result of ultrafast modulation and ultrafast switching of the quantum states in such systems [2]. In this contribution, we study the non-adiabatic switching dynamics of an ultrastrong coupling system composed of two layers of metamaterials in a Fabry-Perot cavity and disclose sub-cycle optical control of the coupling between plasmons and cavity photons. In particular, by ultrafast switching off of one metamaterial, we report the ultrafast transformation of the strong coupling of three quasi-particles into the strong coupling of two quasi-particles.

References:

[1] X. Li, M. Bamba, Q. Zhang, S. Fallahi, G.C. Gardner, W. Gao, M. Lou, K. Yoshioka, M. J. Manfra and J. Kono, “Vacuum Bloch-Siegert shift in Landau polaritons with ultra-high cooperativity”, Nat. Photon., 12, 324 (2018).

[2] M. Halbhuber, J. Mornhinweg, V. Zeller, C. Ciuti, D. Bougeard, R. Huber and C. Lange, “Non-adiabatic stripping of a cavity field from electrons in the deep-strong coupling regime”, Nat. Photon., 14, 675 (2020).