Study On Optical Nonreciprocity In Optomechanical Systems With Quadratic Coupling

Nonreciprocity optical devices can control information transmission in one direction,so they play a non-negligible role in the process of optical communication..On the one hand,photon has become an effective carrier of information transmission because of its excellent characteristics,such as fast response speed,strong parallel processing ability,no charge,strong anti-interference ability,etc,and has been widely concerned by researchers.On the other hand,with the increasing maturity of nanotechnology and semiconductor technology,macroscopic optomechanical systems have more obvious quantum effects,which can effectively realize nonreciprocity.Based on the above background,this thesis mainly studies the nonreciprocal phenomenon in the optomechanical systems with double cavities.Different from the linear optomechanical coupling in previous studies,our optomechanical coupling is Quadratic Coupling.The main contents are as follows:Our research object is the optomechanical systems with three coupling modes.In this model,two cavity fields are coupled with a common mechanical resonator at the same time,and the optomechanical coupling is quadratic interaction.In addition,there is a linear coupling between the two cavity fields,and each cavity field is effectively coupled by the control field and the probe field simultaneously.Starting from the dynamic evolution equation of the system,we get the transmission coefficient of the probe field and prove that the non-reciprocal transmission of light can be realized in such a double optomechanical system with quadratic coupling,and this nonreciprocity is related to the effective phase difference.The physical mechanism of this phenomenon comes from mutual interference with different transmission paths.We analyzed two cases in such a system: red detuning and blue detuning.Through theoretical derivation and numerical analysis,it is found that under appropriate physical parameters,perfect non-reciprocity can be realized in both cases.Our theoretical scheme of realizing the nonreciprocal transmission in a quadratic coupled double optomechanical system provides a theoretical basis for optical circulators,cyclic amplifiers and directional amplifiers.