The analytical expressions for Raman spectra of photons emitted for Rydberg autoionization in a laser field have been derived. The spectral forms for various ratios between the parameters of the problem have been discussed.
The fluorescence produced by an autoionizing state under strong pumping by a coherent laser field is considered. It is shown how the spectrum of emitted photons and the total number of photons are related to the two-time and single-time atomic expectation values, and explicit expressions are derived for them. Numerical results for the time development of the number of photons ejected are presented for finite times and in the long-time limit. The photon spectra are shown to exhibit ac Stark splitting of the states involved. The spectrum is a doublet for transitions to a stable final state and a triplet for transitions connected back to the initial, strongly driven state. The decay of an autoionizing state in the absence of a laser driving field is considered, and the square of the Fano q value is interpreted as the ratio of two decay rates.
We consider laser action on a transition involving an autoionizing state \ensuremath{\Vert}a〉 and an initially unpopulated state \ensuremath{\Vert}f〉, the population of which builds up because of spontaneous emission and Raman processes. The autoionizing state is pumped by a coherent field. We discuss the transient amplification of the probe field on the lasing transition for a range of parameters. The coherent field on the pumping transition leads to minima in the absorption spectra if the atomic population were in the state \ensuremath{\Vert}f〉. Such regions of minima can be used for obtaining gain even for long times.
Spectral features of the radiation emitted by autoionizing states in the presence of a strong laser field are calculated under the condition of multiple photon absorption and emissions. The method is based on the exact solution of the master equation for the recycled system. The decay spectra are found to exhibit sharp maxima at the laser frequency and, for large values of the Fano q value, sidebands which are reminiscent of the triplet which one finds in the context of a two-level atom.