Pulse Lengthening Via Overcoupled Internal Second-Harmonic Generation

Abstract

The paper discusses the use of internal second-harmonic generation as a means of lengthening the pulses of Q-switched lasers. The second-harmonic generator acts as both a nonlinear power-dependent loss and as an output coupler for the laser. The lengthening arises if the coupling to the second harmonic is greater than that necessary to maximize the peak second-harmonic power. It is shown that a pulse-lengthening factor of about 100 should be obtainable.