Interferometric tuning of a 15-atm CO2 laser

Efficient controlled frequency narrowing and tuning of a high-power 15-atm electron-beam-controlled CO2 laser was achieved using a Fabry-Perot etalon as a dispersive element in the laser resonator. Tuning was accomplished over the free spectral range of the etalon (approximately 2.3 cm-1) giving a laser linewidth of less than 0.2 cm-1 for an output pulse energy approximately 100 mJ in a spot size approximately 1 mm2. The laser pulse length is approximately 40 nsec for a peak power approximately 5 MW. (U.S.)