Q-switched diode-pumped Nd:YAG rod laser with output power of 420W at 532nm and 160W at 355nm

Intra-cavity harmonic generation in diode-pumped Q-switched Nd:YAG rod lasers is a preferred architecture to generate high output power at 532nm and 355nm in multimode operation. We have developed a side-pumped, dual rod Nd:YAG laser with intra-cavity second harmonic generation using Type II LBO in a double-pass configuration. A maximum 532nm output power of 420 W was achieved at 10 kHz with an M^2 of about 24. The pulse duration was 70 ns with a pulse energy stability of less than 0.7% rms. By incorporating a novel birefringence compensation technique and adding a Type II LBO sum frequency generator, we attained 160W of 355nm output at a repetition rate of 8 kHz with an M^2 of 18 and a pulse duration of 45 ns.