Thermal Motion-induced Nonreciprocal Optical Bistability Of Three-level Atomic Systems

Optical bistability has attracted much attention in the past few decades because of its excellent switching characteristics.Optical nonreciprocity is widely used in optical isolators,optical circulators,optical amplifiers,optical diodes and other optical components.In recent years,optical components tend to be miniaturized and integrated,so non-magnetic optical nonreciprocal has became the focus of research in recent years.Non-magnetic nonreciprocity can be achieved in the following ways:breaking the spacetime symmetry of the dielectric constant;enhancing the nonlinear of the medium;chiral quantum optical;optical mechanical systems and the Doppler effect caused by the thermal motion of atoms.This paper describes the research status and background of optical bistability and optical nonreciprocity.Combined with the advantages of optical nonreciprocity and optical bistability caused by quantum coherence due to the thermal motion induced by Doppler shifts,a nonreciprocal optical bistability scheme for a three-level atomic system induced by thermal motion is creatively proposed,analyzing the influence of the different system parameters such as:the detuning of the probe field,the detuning of the coupling field,the intensity of the coupling field and cooperation parameters on the frequency width and isolation ratio of nonreciprocal.It is found that optical nonreciprocal transmission based on atomic thermal motion can achieve good isolation effect.The results show that different Doppler frequency shifts occur in the system due to the opposite direction of probe light transmission,which leads to the nonreciprocity of forward and backward transmission.In addition,under the same system parameters,the forward and backward probe fields show different bistability behaviors,and the nonreciprocal isolation ratio and the width of the isolation region can be controlled by adjusting the detuning of the probe field,the detuning of the coupling field,the strength of the coupling field and the cooperation parameters.The research results have certain theoretical significance and application value,and have certain reference significance for the design and implementation of optical nonreciprocal isolators,optical switches and other optical components.