Output squeezed radiation from dispersive ultrastrong light-matter coupling

We investigate the output generation of squeezed radiation of a cavity photon mode coupled to another off-resonant bosonic excitation. By modulating in time their linear interaction, we predict high degree of output squeezing when the dispersive ultrastrong coupling regime is achieved, i.e., when the interaction rate becomes comparable to the frequency of the lowest energy mode. Our work paves the way to squeezed light generation in frequency domains where the ultrastrong coupling is obtained, e.g., solid-state resonators in the GHz, THz and mid-IR spectral range.