Researchers produce high-energy ultraviolet output from Cr:LiSAF
Using a flashlamp-pumped Cr:LiSAF laser system and b-barium borate (BBO) crystals for frequency conversion, researchers at Schwart¥Electro-Optics (Concord, MA) obtained high-energy pulses in the blue and ultraviolet (UV) spectral regions. Pulses with 200-mJ energies at 430 nm represent a 50% conversion efficiency, and second-harmonic generation of this output yielded 40 mJ of energy at 215 nm. The UV energy and conversion efficiency are believed to be the highest obtained from a Cr:LiSAF laser to date, according to team member Henry Zenzie.
The Cr:LiSAF laser performance was optimized by combining a stable resonator with an intracavity telescope. The oscillator was electro-optically Q-switched, and a second Cr:LiSAF rod was used as a double-pass amplifier. Laser output was tuned to 860 nm, and the pulse rate was kept at 2 H¥to minimize laser damage. Improvements in Cr:LiSAF crystal growth yielding higher-quality material may allow operation at higher repetition rates.