Multiwatt high-repetition-rate 2-µm output from an intracavity KTiOPO_4 optical parametric oscillator

Abstract

We have obtained 6.5 W of 2-mum output from a near-degenerate, type II KTiOPO(4) (KTP) optical parametric oscillator (OPO) pumped within the cavity of a Q-switched diode-pumped Nd:YAG laser that operates at 3 kHz. We adopted the simplest configuration with a compact diode-pumped Nd:YAG module pumping the doubly resonant KTP OPO in its randomly polarized resonator with an acousto-optic Q switch. Attempts to increase the 2-mum output power by pumping this intracavity KTP OPO with a polarized laser beam by use of thermal birefringence compensation configurations are discussed.