Continuously tunable optically pumped high-pressure DF → CO2transfer laser

The operational characteristics of a continuously tunable DF → CO
2
transfer laser optically pumped with radiation from a pulsed DF laser are experimentally and theoretically studied. The pump radiation is absorbed by DF in a high-pressure DF/CO
2
/He gas mixture, and subsequent V-V energy transfer to the CO
2
ν
3
mode provides the CO
2
laser population inversion. Continuous tuning of the CO
2
laser frequency between five CO
2
line centers from 29.14 to 29.30 THz has been demonstrated, using a 12 atm gas mixture. The maximum pulse energy was about 0.8 mJ. In experiments with a two-mirror CO
2
laser resonator, pulse energies up to 6 mJ and 35 percent slope quantum efficiency have been obtained at 10 atm gas pressure. The gas mixture typically contained 0.5 percent DF, 5 percent CO
2
, and 94.5 percent He, but this was not critical. Computer simulations based on a rate equation model of the laser have given results which are in reasonable agreement with those obtained experimentally.