Publications

High-cooperativity terahertz landau polaritons in the ultrastrong coupling regime

Li, Xinwei; Zhang, Qi; Lou, Minhan; Reno, J.L.; Pan, Wei P.; Watson, John D.; Manfra, Michael J.; Kono, Junichiro

We have integrated an ultrahigh mobility twodimensional electron gas with a high-quality-factor terahertz photonic cavity. With a quantizing magnetic field and at low temperatures, we demonstrated collective nonperturbative coupling of the electron cyclotron resonance with terahertz cavity photons with a high cooperativity. Due to the suppression of superradiance-induced broadening of cyclotron resonance by the high-quality-factor cavity, our hybrid quantum system exhibited unprecedentedly sharp polariton lines and a large vacuum Rabi splitting simultaneously.