Laser with a saturable absorber-dispersive effects

Abstract

We study the characteristics of the gain function of a laser with an intracavity saturable absorber. Included within the laser cavity is a Fabry-Perot etalon. A semiclassical description of a single mode homogeneously broadened laser system is used. The laser frequency is tuned to the amplifier transition frequency while the absorber detuning is nonzero. In contrast with the usual models, the loss is a simple function of the cavity detuning which in turn depends on the absorber detuning. The etalon characteristic is approximated by an inverted Lorentzian whose relative width proves to be an important parameter. From an analysis of the gain function we conclude that for a suitable combination of parameters the bistability can be purely dispersive. Comparisons are made with the dispersive case of the ordinary optical bistability. We also show that such an arrangement can behave as a filter, suppressing fields within a certain frequency range.