Interaction of non-monochromatic laser field with two-level atom

Abstract

T h e problem of a two-level atom interacting with a non-monochromatic radiation pulse is studied in the resonant approximation for arbitrary detunings, and without the resonant approximation. By using the time-dependent theory of perturbation the analytical expressions for the transition probability and induced dipole moment of the atom are obtained. It is shown that the upper level population of the atom exhibits oscillations that are absent in the resonant approximation. T h e temporal shape of the pulse is shown to affect significantly the atomic transition probability. T h e behaviour of the transition probability and dipole moment spectrum for arbitrary pulse shapes, phases and detunings is investigated. T h e interference between the spectral components arising in nonlinear processes is shown to play a considerable role in the formation of a dipole moment spectrum.