>220W output power at 355nm from a Q-switched diode-pumped solid-state laser

Abstract

We demonstrate 220 W average power at 355 nm from a diode-pumped acousto-optically Q-switched Nd:YAG laser using intracavity second harmonic generation and sum frequency mixing in a nested sub-cavity design. The laser generates linearly polarised pulses with duration 65 ns at repetition rate 10 kHz. Polarisation multiplexing is used to combine two orthogonal beams giving total output pulse energy 22 mJ with peak power <0.3 MW in an unpolarised multimode beam with smooth gaussian-like transverse intensity distribution. The combination of high peak power and high average power in a multimode beam enables the use of low maintenance, low cost of ownership DPSS lasers for high-throughput industrial processes in the UV.