Tunable visible solid-state lasers based on intracavity frequency doubling of Cr:forsterite in KTP

Broadband tunability in the yellow-red region is obtained by use of intracavity type II second-harmonic generation of gain-switched Cr:forsterite lasers in KTiOPO(4) . An operating wavelength range of 67 nm, from 587 to 654 nm, is obtained. Second-harmonic energy of almost 1 mJ is achieved at a peak wavelength of 620 nm. A measured factor-of-34 enhancement in acceptance angle is obtained with broadband harmonic generation. Frequency doubling is optimized with respect to the Cr:forsterite pump and laser parameters.