High-efficiency deep-red laser pumped by doubled Nd:YAG*

Frequency shifting of doubled Nd:YAG laser radiation to 750 and 850 nm in holmium- and erbium-doped lithium yttrium fluoride (YLF) is reported. By resonantly pumping laser transitions in the solid medium, conversion efficiencies of up to 39 percent have been demonstrated and an average power loading of 80 W/cm
³
has been sustained in uncooled operation. This approach provides multicolor capabilities to doubled Nd:YAG lasers, using stable crystalline media.