Effects of atom and nonlinear crystal on quantum properties of cavity light

We examine the cavity modes with a nonlinear crystal and a lambda-type three-level atom coupled to the squeezed vacuum reservoir. The expectation values of the cavity and atomic variables at steady state have been used to determine quadrature variances and logarithmic negativity. The cavity modes exhibit quadrature squeezing and entanglement according to the criteria. The existence of a nonlinear crystal in the cavity and squeezed vacuum reservoir coupling the cavity modes increases the degree of squeezing and entanglement. The coupling constant for atom and cavity modes reduces both the degree of squeezing and entanglement. Furthermore, Duan et al. and logarithmic negativity criteria for entanglement are directly proportional to the variance of the minus quadrature.