Time-dependent spectra of colliding atoms in an intense radiation field

Abstract

The author expresses the time-dependent physical spectrum of any signal as a twofold convolution over frequency and time of the Page-Lampard quasi-spectrum and a smoothing function that is determined by the properties of the spectrometer. This result is applied to the collisional redistribution of intense time-dependent radiation. Without resort to the adiabatic approximation the authors derive a differential equation that determines the time-dependent redistributed spectrum for any given time variation of the incident field. In the special case of adiabatic or sudden switch on the incident radiation he evaluates the approach to the steady state of the fluorescence spectrum of a two-state atom.