粒子数密度对飞秒Gauss型脉冲传播及光谱特性的影响  

Effect of Atomic Density on Propagation and Spectral Property of Femtosecond Gaussian Pulses

作　　者：王振东[1] 杨善迎[2] 刘婷婷[1] 马建玲[1] 肖静[1] 

机构地区：[1]泰山学院物理与电子工程学院,山东泰安271021 [2]莱芜职业技术学院,山东莱芜271100

出　　处：《计算物理》2015年第1期75-85,共11页Chinese Journal of Computational Physics

基　　金：山东省自然科学基金(ZR2011AL011和ZR2009FZ006)资助项目

摘　　要：利用预估校正-时域有限差分(PC-FDTD)法求解全波Maxwell-Bloch方程,研究介质粒子数密度(N)对飞秒Gauss型激光脉冲在Λ型三能级原子介质中传播及光谱特性的影响.结果表明:小面积2π脉冲在不同N介质中都不发生分裂,脉冲频谱基本没有新的高频成分产生,随N增大中心频率附近光谱强度明显减小.面积4π脉冲,在N较大的稀疏介质及稠密介质中都产生分裂,在稀疏介质中随N增大频谱展宽幅度及高频成分强度增大,但在稠密介质中频谱展宽变小且远小于N较大时的稀疏介质情况.大面积8π脉冲,脉冲分裂情况与4π脉冲情况相似,但随N增大频谱展宽幅度及高频成分强度单调增大,且在稠密介质中的频谱展宽幅度及高频成分强度远大于N较小的稀疏介质情况.We investigate effect of atomic densities （ N） on propagation and spectral property of femtosecond Gaussian pulses in a three-level Λ-type atomic medium by using numerical solution of full Maxwell-Bloch equations. It is shown that, for pulses with smaller area 2π, propagate in mediums with different N, pulse splitting does not occur and strength of spectral component near central frequency decreases considerably as N increases. For pulses with area 4π, pulse splitting could occur when pulses propagate in dilute medium with greater atomic density and in dense medium, and pulse spectral bandwidth and strength of spectral component with higher frequency increase with increasing of N in dilute medium. Spectrum broadening in dense medium is much smaller than that in dilute medium with greater atomic density. For pulses with larger area 8π, pulse splitting is similar to that of 4π pulses. Pulse spectral bandwidth and strength of spectral component with higher frequency increase monotonously with increasing of N. And spectrum broadening in dense medium is much larger than that in dilute medium with smaller atomic density.

关 键 词：飞秒Gauss型脉冲 粒子数密度 传播 光谱 

分 类 号：O437[机械工程—光学工程]