Power levels up to 2.8 W have previously been achieved for blue lasers based on frequency doubling of a neodymium laser, but are limited to lower power levels due to considerable reabsorption and thermal losses. Power levels up to 10.1 W have been reported by frequency doubling of tunable lasers in the near-IR region or by blue lasers produced directly through optical parametric oscillators (OPOs); however, these lasers are expensive and often too complicated for routine operation. A simpler blue laser has been developed by researchers at the Chinese Academy of Sciences (Beijing, China) that is based on frequency tripling of a compact Nd:YAG 1319 nm diode-pumped solid-state (DPSS) laser.
To achieve the 7.6 W power output for the 439.7 nm blue laser with 170 ns pulse width, while ensuring high conversion efficiency and long-term stability of better than 1% at a 5.4 W power level, the natural 1338 nm operation wavelength of the Nd:YAG laser was suppressed by using a thin YAG etalon within the folded-mirror resonator design of the cavity. Contact Zuyan Xu at [email protected].