Direct optical pumping of high-pressure CO2and N2O lasers with a pulsed HF pump laser

Pulsed HF laser radiation has been used for direct optical excitation of CO
2
and N
2
O lasers at 10 and 5 atm gas pressures, respectively, which are the pressures required for continuous laser frequency tuning between the line centers in these gases. The maximum demonstrated quantum efficiency is about 14 percent, which seems to be limited by the formation of pressure waves in the gas, in addition to losses in the resonator optics. We find that quantum efficiencies close to unity are theoretically feasible with a low-loss resonator, and by using a sufficiently short pump pulse to avoid a serious influence from pressure waves. The excitation scheme can be used with any of the CO
2
and N
2
O laser isotopes.