Short-pulse multiline and multiband energy extraction in high-pressure CO2-laser amplifiers

The ability of a nanosecond or shorter CO2-laser pulse consisting of a single vibrational-rotational transition to extract energy from an atmospheric-pressure CO2amplifier is limited owing to the finite rotational thermalization time in CO2and the larger number of rotational states which share the stored energy. Theoretical studies are reported which indicate that utilizing an incident pulse consisting of several vibrational-rotational lines within the 10.6-μ band substantial improvements can be obtained over single-line extraction. Even more dramatic improvements are possible if the pulse contains vibrational-rotational transitions at both the 10.6- and 9.6-μ bands. Quantitative energy-extraction results are presented for an input Gaussian pulse consisting of transitions, and for a pulse containing one line at 9.6 μ and one at 10.6 μ, traversing a 1-m amplifier, for a wide range of input energies, pulsewidths, and gas pressures. Possibilities of using multiband techniques for pulse shaping are also discussed.