Quantum properties of nondegenerate three-level laser coupled 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 vacuum reservoir. We obtain stochastic differential equations associated with the normal ordering using the pertinent master equation. By making use of the solutions to the resulting differential equations, we calculate the quadrature variances. We also determine the mean and variance of the photon number for the cavity mode by employing the Q function. It is found that the parametric amplifier increases the degree of squeezing, while the driving coherent light does not have any effect on the squeezing. Moreover, the mean photon number increases considerably due to the driving coherent light and the parametric amplifier.