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.

我们分析了由三级激光器产生的光的纠缠，该三级激光器的腔中包含一个参量放大器，其腔模由相干光驱动并耦合到压缩真空容器中。利用与之相关的主方程产生的与正态有序相关的随机微分方程，获得了双模光的正交方差和纠缠，并讨论了两种光模的光子统计。发现三能级激光器在某些条件下会产生压缩光，最大腔内压缩比相干态水平低89.7％。我们还表明，参量放大器增强了平均光子数和光子数相关性。