Zhenxu BAI, Meng CHEN^*, Jing JIANG, Mingliang LONG, Liyuan CHEN, and Gang LI

Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, P. R. China

(Received February 18, 2013; Accepted May 13, 2013)

A 50.2 W high pulse energy green laser system at 532 nm was demonstrated by extra-cavity second-harmonic generation (SHG). The fundamental laser was based on laser diode (LD) side-pumped MOPA Q-switched technology, producing 79 W of average power at the repetition rate of 500 Hz, while the pulse width was 6 ns. Type-II angle phase-matched KTiOPO₄ (KTP) crystal was used as the nonlinear crystal. The 50.2 W average power of 532 nm laser was obtained with the divergence angle less than 0.6 mrad and the corresponding peak power of 16.7 MW. The optical frequency conversion efficiency from fundamental to green laser was up to 63.5%. The measured output power fluctuation was less than 0.38% in one hour operation.

Key words: laser technique, all-solid-state, Q-switch, MOPA, SHG

^*E-mail address: chenmeng@bjut.edu.cn