CAJ | 학술논문

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。
이용예고교정－시역유한차분（ PC?FDTD）법구해전파Maxwell?Bloch방정，연구개질입자수밀도（ N）대비초Gauss형격광맥충재Λ형삼능급원자개질중전파급광보특성적영향。결과표명：소면적2π맥충재불동N개질중도불발생분렬，맥충빈보기본몰유신적고빈성분산생，수N증대중심빈솔부근광보강도명현감소。면적4π맥충，재N교대적희소개질급주밀개질중도산생분렬，재희소개질중수N증대빈보전관폭도급고빈성분강도증대，단재주밀개질중빈보전관변소차원소우N교대시적희소개질정황。대면적8π맥충，맥충분렬정황여4π맥충정황상사，단수N증대빈보전관폭도급고빈성분강도단조증대，차재주밀개질중적빈보전관폭도급고빈성분강도원대우N교소적희소개질정황。
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.