LOW-FREQUENCY SPECTRUM OF VACUUM SQUEEZED RADIATION TO BE USED IN GW ANTENNAS

We generalize the Collett and Gardiner model for the generation of vac uum squeezed radiation by degenerate optical parametric oscillators. W e account for fluctuating pump, cavity with time varying length and no nlinear crystal phase matching temperature. The equation of motion of the intracavity field is integrated by WKB approximation by introducin g a set of random functions. Relying on this result we calculate the l ow frequency spectrum of the quadrature amplitude, a quantity essentia l for assessing the photon noise reduction in interferometric gravitat ional wave antennas using vacuum squeezed light.