High-power eye-safe intracavity KTA OPO driven by a diode-pumped Q-switched Nd:YAG laser

A high power, high stability, eye-safe intracavity optical parametric oscillator (IOPO) working at the signal wavelength of 1534 nm was demonstrated, in which a type of non-critically phase-matched KTiOAsO4 (KTA) crystals were pumped by a diode-side-pumped acousto-optically Q-switched Nd:YAG laser. When a 25 nun-long KTA crystal was employed, a maximum average Output power of 5.35 W and the minimum pulse width of 3.71 ns were obtained at the maximum 808 urn pump power of 143 W and the repetition rate of 6 kHz, giving an optical-optical conversion efficiency of 31.1% between the signal light at 1534 nm and the fundamental light at 1064 urn. To our best knowledge, it's the highest conversion efficiency for the KTA IOPO driven by diode-side-pumped Nd-doped lasers. The single pulse energy and peak power were determined to be 892 mu J and 287 kW, respectively. The power instability at the maximum output power was observed to be less than 1.72% during one hour. [GRAPHICS] The average output power at signal wavelength of 1534 nm versus the repetition rate under 143 W of pump power with the two KTA crystals