555 nm laser sources based on intracavity frequency doubling of Nd:YGG laser

We report for the first time a yellow-green laser at 555 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1110 nm Nd-doped yttrium gallium garnet (Nd:YGG) laser under in-band diode pumping at 808 nm. An LBO crystal, cut for critical type I phase matching is used for second harmonic generation of the laser. At an incident pump power of 18.5 W, as high as 2.31 W of CW output power at 555 nm is achieved. The optical-to-optical conversion efficiency is up to 12.4%, and the fluctuation of the yellow-green output power was better than 2.8% in the given 4 h.