Increasing the pulse duration of electrooptically Q-switched YAG:Nd3+ laser radiation by intracavity second harmonic generation

A graphoanalytic method is used in an experimental investigation of the space-time characteristics of the radiation from a Q-switched YAG:Nd³⁺ laser with intracavity second harmonic generation (SHG) under 100% conversion conditions. It is shown that deviations from 100% conversion conditions are associated with considerable changes in the spectral composition of the radiation which in turn alter the SHG process. The changes in the space-time characteristics of the radiation ultimately limit the tuning range of the radiation pulse duration under "overconversion" conditions. It is established that the 100% conversion conditions are unstable with respect to alterations in the resonator loading and require additional stabilization.