CONVERSION OF PULSE-PERIODIC CO2-LASER RADIATION TO THE 2ND-HARMONIC IN AGGASE2 CRYSTALS

An investigation was made of pulse-periodic (quasi-cw) conversion, to the second harmonic, of CO2 laser radiation with an energy up to 1.9 mJ per pulse and apeak power of 10 kW. The external conversion efficiency (in terms of the peak power) was 1%. Local heating of a crystal was avoided by moving it transversely across the laser beam. The average pump (first-harmonic) power was 18 W and the second-harmonic power was 22 mW when the pulse repetition frequency was 12 kHz. There was no significant reduction in the conversion efficiency or significant damage to the crystal surface after operation for several hours.