三能级Upper-ladder型系统中的无反转激光相位扩散效应(英文)  

Phase Diffusion Effect on Inversionless Lasing in a Three-level Upper-ladder System

作　　者：朱孟正[1] 赵春然[1] 尹新国[1] 

机构地区：[1]淮北师范大学物胛与电子信息学院,安徽淮北235000

出　　处：《发光学报》2011年第2期174-178,共5页Chinese Journal of Luminescence

基　　金：supported by the Project of Science Research from Education Department of Anhui Province(KJ2009B102);the Fund for Excellent Young talents in the Higher Education Institutions of Anhui Province(2009SQRZ087)~~

摘　　要：三能级Upper-ladder型系统中,在旋波、慢变振幅近似下,求解了考虑驱动场相位扩散后的系统密度矩阵运动方程,并给出了这个三能级梯型系统稳态线性解析解。利用对密度矩阵运动方程的稳态线性解析解的数值模拟结果,研究相位扩散对无反转激光增益、色散和粒子数差的影响;利用对密度矩阵运动方程的数值模拟结果,分析相位的扩散对无反转激光场及相应的各能级粒子数布居的时间演化规律的影响。驱动场相位扩散会导致无反转激光增益减小。线宽的存在阻碍了系统的无吸收高色散。线宽的变化不能改变ladder型系统输出(反转还是无反转)激光的特性。但线宽影响了系统达到稳态的时间以及时间演化过程中的相位扩散将导致相干的减弱。In the rotating wave and slowly varying envelope approximations, the density-matrix motion equations for the three-level cascade system equation are solved under the influence of driving-field phase diffusion. The exact linear analytical solutions of the three-level cascade system with the driving field having the phase fluctuation in the steady state are obtained. The effects of phase diffusion on absorption, dispersion and population difference in a three-level upper-ladder system and on the time of steady-state limit in the course of time evolution have been analyzed by using the numerical simulation from the steady linear, analytical solution and density-matrix motion equations. Gain of the probe field will be decreased due to the driving-field phase diffusion. The presence of the finite linewidth induced by the driving-field phase diffusion prevents the ladder system from obtaining a high refractive index along with zero absorption. Variation of the linewidth can not change the property of the lasing in the upper-ladder system. The linewidth as a result of the driving-field phase diffusion has influence to the time of steady state limit and the phase diffusion leads to a decay of the coherence in the course of time evolution.

关 键 词：激光物理 相位扩散 ladder型系统 

分 类 号：O431.2[机械工程—光学工程] O432.12[理学—光学]