Impact of Thermal Reservoir on Entanglement and Squeezing Characteristics of a Three-Level Laser Driven by Coherent Light in an Open Cavity

Abstract This research aims to study the squeezingand entanglement features of light in three-level atomsunder an open cavity with coherent light excitation.Using an approximation scheme for large timescales,we obtained the steady-state solutions of the evolutionequations for the atomic operators’ expectation valuesand the quantum Langevin equation for the cavity modeoperators. We employed these steady-state solutions todepict the squeezing characteristics, magnification ofentanglement, and normalized second-order correlationof the cavity radiation.The results of our researchshow that the light produced by the three-level lasergets squeezed, mainly in the minus quadrature. Themaximum quadrature squeezing for the light in thetwo-mode cavity is obtained as 37.9% at hni th = 0,and 37.5% at hni th = 0.02, and 37.2% at hni th = 0.03below the vacuum-state level. We demonstrated thatthe average and the variance of the number of photonsdecrease under the influence of spontaneous emission.Moreover, we determined that both the average andthe variance of the photon number are amplified bythe thermal reservoir effect. Additionally, we foundthat quadrature squeezing is enhanced by spontaneousemission, and some entanglement is created. In two-mode light, squeezing and entanglement are directlyrelated, such that an increase in squeezing producesmore entanglement and vice versa.