Resonant self-action and non-stationary coherent transients in frequency-modulated CW laser beams

Periodical modulation of frequency, typical for spectroscopic purposes, is numerically modelled in transversely limited, propagating through a saturable two-level absorber cw laser beams. At modulation periods comparable with the atomic relaxation times the time and frequency dependence of the output intensity exhibits the manifestations of delayed medium response, including time-dependent lens and aperture effects that may be of importance in spectroscopy. Simultaneous manifestation and interaction of resonant self-action and non-stationary transients are analyzed in present work.