Study On Optical Squeezing And Its Transfer In Optomechanical Systems

The optomechanical system(OMS)is a system based on the optical cavity composed of a fixed semi-transmissive optical mirror and a movable optical mirror.The system has potential applications in quantum mechanics,the quantum optics,and quantum information et.al,such as the optomechanically induced transparency,the optomechanically induced absorption,the cooling of mechanical vibrations to their quantum ground states,the quantum entanglement and squeezing and so on.In this paper,we mainly investigate the optical squeezing in the single-mode quadratically coupled optomechanical system as well as its transfer in the two-mode linearly coupled optomechanical system,specifically including two aspects of research work:1.In the single-mode quadratic coupling optomechanical system,we discuss the variation of the output squeezing field of the system with the pump-coupled and the input light field.Then the squeezing in the presence of two nonlinear media including the Kerr and the optical parametric amplifier(OPA)is studied.It is found that the pump light makes the output spectrum appear as a scattering noise in certain frequency regions,however,the output spectrum is squeezed in the other areas,both of them are positively linearly related.The output squeezing spectrum can be greatly adjusted by the input squeezed field.When the system is equipped with nonlinear media,the squeezing can be modulated by adjusting the OPA gain factor and the driving phase: the OPA gain affects the output spectrum in the following ways;the squeezing of the output spectrum is increased by the OPA phase in the range of 0° ~90°,while the squeezing is suppressed by the phase in the range of 90°~180°.However,the Kerr nonlinear medium does not change the maximum value of the output field,but only affects the window width of the output spectrum.The larger the Kerr parameter is,the wider the window of the spectrum becomes.These results will help us to flexibly modulate the squeezing of the optical field in the optomechanical system.2.We study how the squeezing of the injected field in one cavity of the two-mode linearly coupled optomechanical system is transferred to the output spectrum from the second cavity.It is found that the squeezing of the output spectrum can be generated by the optomechanical interaction or by the transfer from the input squeezed field.The squeezing of the output field increases with the input squeezed field.In addition,this paper considers the effects of the environmental thermal bath on the squeezing of the output spectrum.When injecting the vacuum field into the left cavity,the thermal bath of the mechanical oscillator provides the thermal phonons,which can enhance its noise and suppress the squeezing effect caused by the optomechanical interaction.While injecting the squeezed field into the left cavity,the adverse effects of the thermal bath on the output squeezing spectrum can be effectively suppressed.This study is not only useful in comprehending the squeezing properties in the optomechanical systems but also benefits the quantum information and quantum transfer et.al.