Optically pumped laser action in dideuteroacetylene

Optically pumped laser action has been observed in dideuteroacetylene. A total of fifteen output wavelengths in the 17.4 to 20.5 μm region are produced, pumped by seven CO₂ laser lines. The laser shows a number of unusual features, in particular pumping on hot bands and formally forbidden transitions and operation at high pressure (65 torr). Output energies were ～ 2 mJ from an unoptimised system. The temperature and pressure dependence of the output energy has been measured for typical lines. The time dependence of the output pulse varies markedly between the various output lines and suggests that one transition is Raman in origin.