Compact efficient intracavity optical parametric oscillator with a passively Q-switched Nd : YVO4/Cr4+: YAG laser in a hemispherical cavity

Abstract

A compact eye-safe optical parametric oscillator (OPO) using a noncritically phase-matched KTP crystal intracavity pumped by a passively Q-switched Nd: YVO4 laser is experimentally demonstrated. To enhance the performance of passive Q-switching, a Cr4+: YAG saturable absorber crystal is coated as an OPO output coupler in a nearly hemispherical cavity. With an incident pump power of 2.5 W, the compact intracavity OPO cavity, operating at 62.5 kHz, produces average powers at 1573 nm up to 255 mW and peak powers higher than 1 kW.