Study on energy scaling of 1.3 μm dual-wavelength Nd:YAG laser

Abstract We demonstrate a high-energy dual-wavelength Nd:YAG solid-state laser emitting at 1.3 μ m. To scale up the laser output power and beam quality, the resonator has a two-rod configuration side-pumped by a quasi-continuous wave, pulsed laser diode instead of a continuous wave format, so as to mitigate the thermal effect in the laser crystal effectively. Two acousto-optic Q-switches are adopted to obtain higher peak power. By precise coating on the cavity mirrors, simultaneous oscillation at 1319 and 1338 nm is achieved with the intension ratio of near 59:50. The oscillator operates at a repetition frequency of 400 Hz and pulse duration of 117 ns, delivering a maximum average output power of 49.4 W with an optical-to-optical conversion efficiency of 12%. The calculated peak power and pulse energy are up to 1.06 MW and 123.5 mJ, respectively, which is, to our best knowledge, the highest energy Nd:YAG laser in the 1.3 μ m region.