Coherently driven nondegenerate three-level laser coupled to squeezed vacuum reservoir

In this paper we have studied the squeezing and statistical properties of the light produced by a three-level laser whose cavity contains a parametric amplifier and with the cavity mode driven by coherent light and coupled to a squeezed vacuum reservoir. We obtain stochastic differential equations associated with the normal ordering using the pertinent master equation. Making use of the solutions of the resulting differential equations, we calculate the quadrature variances. We also determine the mean and variance of the photon number for the cavity mode employing the Q function. It is found that the parametric amplifier and squeezed vacuum reservoir increase the degree of squeezing, but the driving coherent light does not have any effect on the squeezing. Moreover, the mean photon number increases considerably due the driving coherent light, the parametric amplifier, and the squeezed vacuum reservoir.