准Λ型四能级系统选择反射光谱  

Selective reflection spectrum in a quasi-lambda four-level atomic system

作　　者：孟腾飞 田剑锋[1] 周瑶瑶 Meng Teng-Fei;Tian Jian-Feng;Zhou Yao-Yao(Department of Physics,Taiyuan Normal University,Jinzhong 030619,China)

机构地区：[1]太原师范学院物理系

出　　处：《物理学报》2020年第1期265-271,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11804246)资助的课题~~

摘　　要：运用密度矩阵理论研究了气固界面准Λ型四能级原子系统的非线性选择反射光谱.基于刘维尔方程给出了一阶近似条件下探测光场的解析式.在探测场为弱场时,分析了信号场拉比频率、失谐量和耦合场失谐量对反射光谱线型的影响.数值模拟表明:信号场参与产生的选择反射峰线宽可以利用信号场拉比频率进行调节,通过调节信号场频率失谐量,可以实现选择反射峰到透明窗口的转化,选择反射峰和透明窗口的位置可以通过耦合场失谐量实现调谐.利用三种电子跃迁路径以及缀饰态理论对所得结果进行了解释.本文结果为研究气固界面原子的量子相干和动力学过程提供理论参考.Selective reflection(SR)from the interface between transparent medium and dilute vapour is caused by the atomic vapor near the interface.The sub-Doppler structure in SR is due to the deexcitation caused by the collision between atomic vapor and the wall.Beacuse the interaction region between atomic vapor and incident light is on the order of a few hundred nanometers,SR has low optical loss and high spatial resolution.The experimental device of SR is simple.Because of the above characteristics,the SR has been widely studied and applied.The nonlinear SR spectrum of quasi lambda-type four-level system at gas-solid interface is studied theoretically in this paper.By sloving the density matrix equations,the approximate analytic solution of the matrix element associated with the probe field is obtained at normal incidence when the intensity of the probe field is very weak.The effect of the Rabi frequency,the detuning of the signal field and the detuning of the coupling field on the lineshape are analyzed by numerical simulation,respectively.Three peaks and two transparent windows appear in SR spectrum when the detuning of coupling field and signal field are both zero.The middle peak is generated due to the participation of signal field,and the other two peaks are caused by the other two fields.The linewidth and the amplitude of the middle peak can be changed by varying the Rabi frequency of signal field,and the other two peaks have little effect on the Rabi frequency of signal field.The signal generated due to the participation of signal field can be transformed from peak to transparent window when the detuning value of the signal field is equal to the Rabi frequency of coupling field.When the detuning value of the signal field is not equal to the Rabi frequency of coupling field,a dispersion-like signal between reflection peak and transparent window is generated due to the participation of signal field.The position of peak and transparent window can be manipulated by controlling the detuning value of the coupling fiel

关 键 词：选择反射光谱 电子跃迁 缀饰态 准Λ型四能级系统 

分 类 号：O41[理学—理论物理]