Generation of entanglement from a two-mode cascade laser

We analyse the entanglement of the light produced by a three-level laser whose cavity contains a parametric amplifier, with the cavity mode driven by the coherent light and coupled to a squeezed vacuum reservoir. Employing stochastic differential equations associated with the normal ordering resulted from the pertinent master equation, the quadrature variances and entanglement of the two-mode light are obtained and photon statistics of the two-light modes is discussed. It is found that the three-level laser generates squeezed light under certain conditions, with maximum intracavity squeezing being 89.7% below the coherent state level. We also show that the parametric amplifier enhances the mean photon number and photon number correlation.(author)