Magneto-optic And Phase Modulation Of The Gooss-Hanshin Shift In Cavity-coupled Coherent Atomic Systems

When the reflection or refraction phenomenon happens at the interface of the different two media,the distance between the actual exit position of the beam and the position predicted by the geometric optics in the incident plane,which is called Goos-H?nchen shift(GH shift).The enhancement and control of the GH shift has certain practical significance in optical devices such as temperature sensors,displacement sensor,refractive index sensor and optical switches.Early,people mainly investigated the influence of parameters such as the material and structure of the medium on GH shift.In recent years,it was discovered that by using optical phenomena such as electromagnetically induced transparency,the value and direction of the GH shift can be adjusted in a multilevel atomic system.Based on the quantum coherence effect,the GH shifts of reflected and transmitted beams in cavity coupled four-level atomic system are analyzed.The effects of magnetic field,light field strength and phase of the light field on the GH shift are studied,the specific content is as follows:1.Based on the cavity coupled tripod four-level atomic system,the variation of the absorption dispersion properties of the atomic system and the GH shifts of the reflected and transmitted beams are studied.By applying a magnetic field to the transition,Pe=0?Fg=1,a tripod-type atomic system is obtained due to Zeeman splitting of the energy level.Using a TE and TM polarized light as the coupling and probe fields,respectively,the Rabi frequency of the light field and the splitting width of the energy level(proportional to the magnetic field strength)on the absorption dispersion properties of the atomic system and the GH shifts of reflected and transmitted beams are investigated.In the first model,the TM polarized light is used as the coupling field,and the TE polarized light is used as the probe field as the cavity medium.Due to quantum interference effect,as the Rabi frequency of the coupled light field increases,the absorption of the atomic system gradually weakens at resonance,and the GH shifts of reflected and transmitted beams gradually increase,and the change of the shift of the reflected beam is more obvious.With the increase of the magnetic field strength,the change of absorption and GH shift is exactly the opposite.In the second model,TE polarized light is used as the coupling field and TM polarized light is used as the probe field.As the Rabi frequency of the coupled light field and magnetic field strength increase,the absorption of the atomic system first increases and then decreases at the resonance,but the GH shift is first reduced and then enhanced.In addition,in the two models,the magnetic and the light field are used to transform the atomic system from transparent to weak absorption at the resonance,so that the shift of the reflected beam is changed from positive to negative.In this scheme,the GH shift is inversely correlated with the absorption of the system.The value and direction of the GH shift are manipulated by changing the applied light field and magnetic field,which can be used in optical devices such as optical switches.2.The GH shifts of reflected and transmitted light in a cavity coupled four-level atomic system with closed interaction contour was explored.The absorption and refractive index of the atomic system are not only affected by the Rabi frequency of the external field,but also related to the relative phase of the external field.Therefore,the GH shift can be adjusted by the intensity and phase of the applied field.As a result,at the resonance,the absorption of the atomic system and the GH shifts of the reflected and transmitted light changes periodically with the phase in a period of 2?,and both are horizontally mirror-symmetrical with the axis of ?=?,the weaker the absorption,the larger the shift value,The refractive index of the system with closed interaction contour also changes periodically with the phase in a period of 2?,the larger the refractive index,the larger the resonance angle at which a significant shift occurs,and both have the exactly same change trend with phase.Therefore,the angle of the GH shift peak can be adjusted by the phase.When the phase is zero,as the Rabi frequency of the coupling field increases,the absorption of the system with closed interaction contour gradually weakens,and the GH shifts of reflected and transmitted light gradually increase,as well as the refractive index and resonance angle of the system both increase first and then decrease.The scheme verified the inverse correlation between the GH shift and the absorption of the system,and the resonance angle determined by the refractive index of the system at different probe field detuning.It has potential applications for beam control in regulating GH shift through the phase and intensity of the light field.