Externally induced entanglement amplification in a coherently pumped emission of laser with parametric amplifier and coupled to squeezed vacuum reservoir

Abstract

Externally induced entanglement amplification in a coherently pumped Correlated Emission Laser (CEL) with parametric amplifier and coupled to a squeezed vacuum reservoir is presented. The combination of the master equation and stochastic differential equation is applied to investigate the entanglement of the correlated two photons generated by the quantum system. The resulting solutions of the correlation properties of noise forces associated with the normal ordering are used to find the mean photon number of the separate cavity modes and their correlation, EPR-pair variables, and smallest eigenvalue of the sympectic matrix. It is found that pumping atoms from the lower energy state to excited state results in a strong entanglement that remains in its maximum strength over a wide range of the strong classical pumping radiation. The introduction of the nonlinear crystal into the laser cavity, and coupling the system to the two-mode squeezed vacuum environment lead to a significant enhancement of entangled cavity light. The entanglement produced is quantified employing logarithmic negativity, Hillary Zubairy and Duan et al criteria. It has been observed that an intense light can be produced where the entanglement is strong. The amount of the entanglement produced is found to be 87% by both Duan et al and logarithmic negativity criteria.