频率受随机过程调制的体系中的光谱扩散

通过在Bloch方程中增加描述对频率微扰的随机过程项{ω(t)},我们讨论了系统在窄谱带的光激发后的光谱扩散。特别是以下两种情况:1)如果ω以相同的概率变化为系综中的任一ω’,光谱是一个指数式衰减的定域峰和指数式增长的动态非均匀背底的叠加。2)如果ω'到ω的概率仅与|ω’-ω|有关,非定域峰随时间变宽。作为一个例子,我们讨论了频率受多个独立随机电报过程调制的系统中的光谱扩散。

SPECTRAL DIFFUSION IN THE SYSTEMS WITH RANDOM FREQUENCY MODULATION

By introducing terms describing the random frequency modulation into optical Bloch equation, we have discussed spectral diffusion in such systems after a narrow band excitation. Especially, 1) if ω jumps to any other ω′ in the ensemble with equal probability, the time dependent lineshape would be a superposition of an exponentially decayed localized line and an exponentially grown background; 2) if the probability that ω jumps to ω′ depends on |ω′-ω|, the delocalized peak would be broadened with time. We have also discussed spectral diffusion in the system with frequency modulated by numbers of independent random telegraph processes as an example.