Investigation of a high-pressure continuously tunable CO2 laser

An experimental and theoretical investigation was made of the frequency tuning of a pulse electron-beamcontrolled CO₂ laser. A continuous tuning was achieved in a range of ~45 cm^–1 and the energy per pulse was ~0.1 J when the pressure in the laser mixture was 5 atm. The frequency pulling of the multimodestructure envelope of the gain lines was observed. This pulling was practically eliminated by inserting in the resonator a lens telescope or a prism, which increased the diameter of the beam on a diffraction grating. The spectral width of the radiation was ~0.05 ^–1. The results of a theoretical calculation of the tuning characteristics of the laser were close to the experimental data. A continuously tunable CO₂ laser was used in resonant excitation of visible luminescence in ethylene and optoacoustic detection of deuterated molecules HDS and NH₂D in natural isotopic mixtures of hydrogen sulfide and ammonia.