High Power Q-switched TEM_(00) Mode Diode-Pumped Solid State Lasers with > 30W Output Power at 355nm

摘要

Since their first commercial introduction in 1997, diode-pumped Q-switched vanadate and YAG lasers with 355nm output have advanced in power level and reliability and are now qualified in many industrial processes, such as via hole drilling, stereo lithography, wafer scribing and dicing. At present, average output power of up to 20W at 355nm are commercially available with pulse energies of several hundred micro-Joules and pulse repetition rates of up to 150 kHz. In this paper, we report high power UV generation with TEM_(00) mode output powers in excess of 30W in Q-switched, end-pumped Nd:YVO_4 and side-pumped Nd:YAG lasers using extra-cavity sum frequency generation in LBO. With a side-pumped dual-rod Nd:YAG rod oscillator and extra-cavity tripling, 32W output power at 355nm have been achieved at a repetition rate of 50 kHz. With an end-pumped vanadate MOPA configuration, UV average power of 36W with TEM_(00) mode was realized at repetition rates around 100 kHz. Lifetest results are presented and the scaling to higher UV power of more than 60W is discussed.