We analyze the possibility of creating photons from a vacuum due to the dynamical Casimir effect in a nondegenerate cavity with vibrating boundaries, taking into account losses and detuning from the exact resonance. Explicit analytical solutions of the equations for the quadrature variances of an equivalent field oscillator with a time-dependent frequency show that photon generation is possible provided the relative detuning and inverse quality factor do not exceed a critical value of the order of ${10}^{-8}.$ Under this condition, the field goes finally to a highly squeezed quantum state.

• Received 13 August 1997

DOI:https://doi.org/10.1103/PhysRevA.58.4147