双光场作用下的粒子数布居反转  

Population Inversion Under Driven of Double Laser Fields

作　　者：张贵银[1] 武晓蕊 李松涛[1] 郑海明[2] Zhang Guiyin;Wu Xiaorui;Li Songtao;Zheng Haiming(School of Mathematics and Physics,North China Electric Power University,Baoding 071003,Hebei,China;Department of Mechanical Engineering,North China Electric Power University,Baoding 071003,Hebei,China)

机构地区：[1]华北电力大学数理系,河北保定071003 [2]华北电力大学机械工程系,河北保定071003

出　　处：《激光与光电子学进展》2023年第7期253-258,共6页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(11174078);河北省自然科学基金(A2019502044)。

摘　　要：采用开放的梯形三能级原子模型及密度矩阵方程理论,数值模拟了不同参数条件下,双色双光场多光子电离过程中粒子数布居随时间的变化。发现两束激光频率失谐量均为零时,基态、第一、第二共振态粒子数布居随时间呈现振幅减小的拉比振荡,第一共振态布居振荡的频率是基态和第二共振态布居振荡频率的两倍,第二共振态和基态之间可存在较大粒子数布居反转,为实现短波长脉冲相干光输出提供了可能,且激光拉比频率越高,布居振荡频率及粒子数布局反转差值越大。两束激光同步作用于系统,亦有利于粒子数布居反转。Based on the open trapezoidal three-energy level atomic model and density matrix equation theory,the variation of population with time during double-color and double-resonant enhanced multiphoton ionization is numerically simulated under different parameters.When the frequency detuning of two lasers is zero,the populations of the ground as well as first-and second-excited states exhibit damping Rabi oscillation with time.The oscillation frequency of the population distributed in the first-excited state is twice that in the ground and second-excited states.Large population inversion occurs between the second-excited and ground states and exhibits the possibility for the output of coherent light with short wavelengths.Furthermore,the oscillation frequency and population inversion increase with Rabi frequency.Population inversion is evident as the two lasers become synchronous.

关 键 词：非线性光学 双共振多光子电离 密度矩阵方程 布居反转 时间延迟 

分 类 号：O433.54[机械工程—光学工程]