Design and implementation of orthogonal gain type passively Q-switched laser

In order to improve the stability of the passively Q-switched pulses, the gain orientation of the Nd:YVO4 was taken advantage and an electro-optic crystal was used to rotate the line polarized light vector by 90, then the intracavity gain mutation can be realized, thereby stable output of the passively Q-switched was realized. Through this method, when the reflectivity of the coupling output mirror was 80% and the initial transmittance of the saturated absorber was 83.06%, the output power reached 4.68 W at a given pump power of 22 W, high repetition rate output with repetition frequency of 49.16 kHz and the pulse width of 26.28 ns was obtained in the experiment of LD continuously pumped Nd:YVO4 passively Q-switched. In the case of the pump current from 10 W to 22 W, a stable passive Q laser output was obtained. The pulse-to-pulse amplitude fluctuation was less than 2.4%. The inter-pulse timing jitter of the Q-switched pulse train was found to be less than 5%. The instability of repetition rate was less than 1%. For a slope efficiency of 34%, the corresponding optical-to-optical conversion efficiency reached 21.27%.