Pulse compression in continuously pumped dye lasers with a slow saturable absorber

Conditions for pulse compression and stability in a system of spatially separated amplifier and absorber contained in a ring or a common two-mirror cavity are investigated theoretically. The width of the pulse that travels in the cavity is assumed to be short compared to the longitudinal but long to the transversal relaxation times of the amplifier and the absorber (rate-equation theory). Especially the smallest ratios of the cross sections of the absorption and the stimulated emission needed for pulse shortening are calculated by analytical and numerical treatment.