Stability criteria for non-Doppler lasers

Under some conditions many types of laser oscillators are known to produce their output in the form of an infinite periodic pulse train, even when the pump rate and cavity losses are independent of time. For some lasers the underlying cause of the instability is well understood, while for others the source of pulsations remains unknown. Emphasis here is on a coherent pulsation effect which previously has only been analyzed in relation to Doppler-broadened gas lasers. The same effect is shown to apply also to lasers with non-Doppler line broadening and the governing stability criteria are derived.