Kilohertz pulse repetition frequency slab Ti : sapphire lasers with high average power (10 W)

High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a ki lohertz pulse repetition frequency copper vapor laser (CVL), were demonstra ted. These lasers are designed for damage-free power scaling when pumped by CVL's configured for maximum output power (of order 100 W) but with poor b eam quality (M-2 similar to 300). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-ns FWHM pulse duration at an absolute efficiency of 15% (68-W pump powe r). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping l evel for commercially available Ti:sapphire (0.25%). A Slab laser with a mu ltiply folded zigzag path was therefore designed and implemented that produ ced high-beam-quality (TEM00-mode) output when operated with cryogenic cool ing and provided a longer absorption path for the pump. Excessive scatterin g of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, ga in measurement, and modeling suggest that efficient power extraction (>15 W TEM00 >23% efficiency) from this laser would be possible for crystals with an optical quality surface polish. (C) 1999 Optical Society of America. OC IS codes: 140.3580, 140.3600, 140.3590, 140.6810.