Efficient acousto-optic Q-switched Nd, Mg:LiTaO3 lasers

An acousto-optic Q-switched Nd, Mg:LiTaO3 crystal laser with π-polarized output at 1082.3 nm is reported for the first time. With a pumping power of 6.5 W at 808 nm, the maximum achieved pulse energy is 0.12 mJ, with a pulse width of 92 ns, corresponding to a peak power of 1.3 kW, which represents the highest peak power from rare-earth-doped ferroelectric crystal lasers. At high pump power, a photorefractive phenomenon and self-frequency-doubling are observed. Self-repairing features of the Nd,Mg:LiTaO3 laser via interaction between the walk-off effect and the thermal photorefractive effect to improve output stability are also discussed. Furthermore, in a continuous-wave laser operation, the slope efficiency is 14.8% with respect to absorbed σ-polarized pump power, which is 6.7% higher than that of 8.1% obtained with non-polarized pumping.