A self-seeded gain-switched semiconductor laser is applied as a fundamental optical source to second-harmonic generation, and improvement of frequency-conversion efficiency is demonstrated. 345-nm ultraviolet light of 0.12-μW average power is generated in a bulk LiIO<sub>3</sub> crystal for 690-nm fundamental light of 10.5-mW average power, which is composed of 500-MHz pulse trains emitted from an AlGaInP diode laser with a 68-ps temporal width and a 0.11-nm spectral bandwidth. It is clearly shown that the narrowing of the spectral bandwidth by the self-seeding technique gives rise to a normalized conversion efficiency of 0.218%/Wcm , which is fourtimes larger than that for pulses without seeding.
© 1997 Optical Society of America
Yasuhiro Uchiyama, Masahiro Tsuchiya, Hai-Feng Liu, and Takeshi Kamiya, "Efficient ultraviolet-light (345-nm) generation in a bulk LiIO3 crystal by frequency doubling of a self-seeded gain-switched AlGaInP Fabry Perot semiconductor laser," Opt. Lett. 22, 78-80 (1997)