Efficient eye-safe intracavity KTP optical parametric oscillator

摘要

This paper describes the development and performance of an optical parametric oscillator based on KTP crystal and pumped by a flashlamp-pumped Q-switched Nd:YAG laser at 1.064μm. The effect of an optical resonator configuration on OPO performance has been investigated experimentally. A comparison between plane-parallel, stable and unstable resonators in both energy conversion and output beam divergence was also performed and the results are discussed. In summary, we have demonstrated a compact low threshold source for the near IR in a configuration of an intracavity optical parametric oscillator based on the noncritically phase-matched KTP crystal placed inside the resonator of a multi-transverse-mode Nd:YAG laser. The 1.57μm output energy of 40 mJ was achieved with a stable, short cavity KTP OPO. The overall efficiency (flashlamp input to OPO signal-wave output) of 0.55% was obtained from operating ～2 times above oscillation threshold. The dependence of output pulse energy on flashlamp input energy was not changed within the range of 5-50 Hz.