Unidirectional saturation spectroscopy,II

The general probe absorption coefficient derived in Part I is specialized to homogeneous- and inhomogeneous-broadening limits and illustrated as the dipole lifetime is increased from 0 to values comparable to the level lifetimes. This progression reveals the relation between pulsation dips of the short-dipole lifetime limit and the dynamic Stark effect in general. Interpretations of the coherent interactions involved are given in terms of modulator and Raman effects and of dressed atoms. The single-probe unidirectional pulsation dip is shown to be a special case of the grating dip in which the fringe spacing becomes infinite. Analogies with three-level systems are given in which both two and three-level cases are seen to obey an “equal-area theorem”, and to involve level crossing. Some comparison is made with corresponding spectroscopy in which spontaneous emission provides the probe radiation. Work performed as a Humboldt awardee in Germany. Work supported in part by the Space and Missiles Systems Organization, Los Angeles, California. Work supported by the Deutsche Forschungsgemeinschaft