摘要
The effect of fourth-order coherence on ultrafast modulation spectroscopy(UMS)with phase-conjugation geome-try(PCUMS)in a cascade three-level system is investigated using chaotic and phase-diffusion models.It has been found that the modulation terms of the beat signal depend on.the second-order coherence function,and different stochastic models of the laser field affect only the fourth-order coherence function.The difference between the PCUMS and UMS is discussed from a physical viewpoint.
基金
Supported by the National Natural Science Foundation of China under Grant No.69978019.
