DYNAMICS OF Q-SWITCHED AND MODE-LOCKED INTRACAVITY 2ND HARMONIC-GENERATION IN A RING LASER

We describe the temporal dependence, spectral characteristics, and efficiency of a multimode Q-switched ring laser containing an intracavity second harmonic generator. Numerical studies show that such lasers are stable and efficient. Comparison with Q-switched lasers (not containing a second harmonic generator) demonstrates that the intracavity second harmonic generation lasers can be even more efficient than the fundamental laser due to nonlinear output coupling. General considerations for the operation of such lasers are described. Spectral characteristics of the output as a function of the gain of the active medium and the spectrum of the injected pulse are discussed. Instabilities at very high second harmonic conversion are observed. The temporal evolution of short duration (mode-locked) pulses injected into a regenerative amplifier is studied. The dynamics of a mode-locked intracavity second harmonic generator ring laser is also considered.