A diodepumped Nd:YAG laser configured with a ring resonator has produced 4.5 W of singlefrequency CW output at 1.064 µm and, when frequencydoubled with KTP, more than 3 W at 532 nm. Researchers at the Optoelectronics Research Centre (ORC, University of Southampton, England) obtained these results using a beamshaping technique they developed that enables the highly elliptical output beam of the 20W diodebar pum¥laser to be focused to a circular spot of less than 200µm diameter (see Laser Focus World, May 1994, p. 46). According to David Hanna, professor of physics at ORC, the system is not yet optimized, and he expects further significant increase in green, singlefrequency output power. The beamshaping technique, which has been patented by the university, should be useful in any application requiring an intense output beam.
Lowest thresholds reported for 1.3micron laser diodes