Second Harmonic Generation of Short Pulse, High Peak-Power, Line-Narrowed TEA CO2 Laser Using a AgGaSe2 Crystal

Second-harmonic generation (SHG) of short pulse, high peak-power, line-narrowed TEA CO2 laser radiation has been demonstrated for the typical vibrational-rotational transition lines of 10P, 10R, 9P and 9R branches in a 15-mm long AgGaSe2 crystal with broad band AR coatings. A high energy conversion efficiency of 38% with the SHG output energy of 7.4mJ (274 kW peak power) was achieved in triple-pass at a moderate pumping intensity of 5.7 MW/cm2. Multi-pass pumping scheme is a very powerful technique to enhance conversion efficiency.