Abstract

Recent work in optical spectroscopies has shown how the amplitude and phase properties of the driving fields can significantly control the spectral response of a sample. This is particularly true for nonlinear spectroscopies where higher-order time correlation functions become important. It is only necessary that the spectral density of the appropriate field correlator match or exceed the damping widths of the spectroscopic system under study. In principle, recently in practice, phase and amplitude control, including multiple pulsing, led to the optical analog of NMR experiments. Even naturally incoherent light sources, properly manipulated, can provide information about the spectroscopic system on the time scale of the coherence time of the source. Furthermore, incoherence in the incident light can generate the same complex line shapes and new resonances that are otherwise caused by quasi-elastic pure-dephasing system/material bath interactions. A brief outline of these developments will be given. By way of specific example, preresonant and resonant spontaneous secondary radiation is discussed. Here only two driving fields are present yet it is seen how the spectral density of their correlation function can confer a complex spectral behavior even in a simple three-level system.

© 1986 Optical Society of America