Tunable yellow–green laser based on second harmonic generation of LiF:F−2 in KTP

A yellow–green solid-state laser source based on frequency- doubling of a room temperature LiF:F−2 laser in KTP is reported. Second harmonic generation of free-running and prism-tuned pulsed lasers has been characterized. Tunable operation between 555 and 595nm was obtained, with a conversion efficiency of 7.5% for the free-running laser, and up to 4% for the prism-tuned configuration. The angular bandwidth of 60milliradians exceeded the theoretical value by a factor of 3.5. A flattened tuning curve in the visible region was obtained through enhanced conversion efficiency in the wings of the LiF:F−2 laser tuning range.