Physical Review A
Nonlinear-resonance line shapes: Dependence on the transverse intensity distribution of a light beam
А. В. Тайченачев, Anatolii M Tumaikin, Valeriy I. Yudin, M. Stähler, R. Wynands, John E. Kitching, Leo W. Hollberg
Abstract
We analyze the line shape and width of atomic coherent-population-trapping (CPT) resonances excited by laser beams with different transverse intensity profiles. A dramatic difference in the resonance line shape is found when comparing a beam with a ``steplike'' profile to a beam with a Gaussian profile. In particular, for nonuniform profiles, a non-Lorentzian functional form is given that is more appropriate for describing the nonlinear resonance line shape than is a conventional Lorentzian. Our analysis is supported by measurements of CPT line shapes in a thermal vapor of ${}^{85}\mathrm{Rb}.$