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

Broadband tunability in the yellow-red region is obtained by use of intraca vity type II second-harmonic generation of gain-switched Cr:forsterite lase rs in KTiOPO4. 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 wa velength of 620 nm. A measured factor-of-34 enhancement in acceptance angle is obtained with broadband harmonic generation. Frequency doubling is opti mized with respect to the Cr:forsterite pump and laser parameters. (C) 1999 Optical Society of America OCIS codes: 140.3580, 140.7300, 140.3600, 190.7 220, 190.2640.