  We present and investigate an analogue model for a controllable photon
geberation via the dynamical Casimir effect (DCE) in a cavity containing a
degenerate optical amplifier (OPA) which is pumed by an amplitude-modulated
field. The time modulation of the pump field in the model OPA system is
equivalent to a periodic modulation of the cavity length, which is responsible
for the generation of the Casimir radiation. By taking into account the rapidly
oscillating terms of the modulation frequency, the effects of the corresponding
counter-rotating terms (CRTs) on the analogue Casimir radiation emerge clearly.
We find that the mean number of generated photons and their quantum statistical
properties exhibit oscillatory behaviors, which are controllable through the
modulation frequency as an external control parameter.We also recognize a new
phenomenon, the so-called "Anti-DCE," in which pair photons can be coherently
annihilated due to the time-modulated pumping. We show that the Casimir
radiation exhibits quadrature squeezing, photon bunching and super-Poissonian
statistics which are controllable by modulation frequency. We also calculate
the power spectrum of the intracavity light field. We find that the appearance
of the side bands in the spectrum is due to the presence of the CRTs.
