Exploring the dynamical Casimir effect via resonator frequency modulations

We propose a protocol to study the dynamical Casimir effect (DCE) in an optomechanical system involving a frequency-modulated resonator with a vibrating mirror. The frequency modulation changes the resonant condition of the photon-phonon parametric coupling and then makes the photons generated by the DCE become more observable. Through the vacuum Casimir-Rabi splitting, the generation of photons from the DCE is demonstrated. Meanwhile, numerical simulations show that when driving the mechanical mode, the system is able to emit observable photon fluxes, even though the resonator frequency is much larger than the mechanical frequency. The results also validate the protocol is robust to the resonator decay and the modulation parameters. Thus, our protocol paves the way to explore the DCE for cavity optomechanical systems.