Passively Q-switched intracavity single resonant optical parametric oscillator and Cr4+：YAG laser

The characteristics of the Cr4+:YAG laser and single resonant optical parametric oscillator(SRO) pumped intracavity by a passively Q-switched Nd3+:YAG laser are analyzed using Cr4+:YAG as the saturable absorber and laser gain medium.The rate equations describing the dynamic characteristics of this kind of laser and intracavity SRO(ICSRO) are set up.Under suitable conditions,the Cr4+:YAG laser gain medium can amplify the SRO signal wave generated in the second-order nonlinear interacting process if the wavelength of this wave is in the range of the gain spectra of Cr4+:YAG.The influence of intermediate level on the Cr4+:YAG saturable absorber and laser as well as ICSRO are considered in the analysis.This intermediate level between the higher excited state and the upper laser level has a relaxing time constant of approximate 100ns.