Observation of hybrid plasmon-photon modes in microwave transmission of coplanar microresonators

Abstract

Microwave transmission of a coplanar microresonator deposited on a sample surface over a two-dimensional electron system has been studied. The transmission signal reveals a series of resonances corresponding to the excitation of hybrid cavity plasmon-photon modes, and ultrastrong plasmon-photon coupling has been realized. The hybridization frequency (Rabi frequency) is shown to be anomalously larger than the frequencies of unperturbed modes and it reaches values of up to $25$ GHz. The effect of electron density and magnetic field on the excitation spectrum of cavity polariton has been investigated.