Generation of multiband tunable radiation in TEA CO2 lasers

A method for generating multiband tunable radiation in TEA CO₂ lasers is described. Simultaneous lasing in all four branches of the 10⁰0← 00⁰1 and 02⁰0← 00⁰1 vibrational — rotational bands of CO₂ was achieved. Frequency tuning in each of the bands in multiband lasing was ensured by introduction of selective absorbers (SF₆, CF₂HCl, CF₃I) and/or parallel CaF₂ or BaF₂ plates into a two-mirror laser cavity. The frequency in a selected band was tuned with the aid of an additional cavity formed by a diffraction grating, a beam-splitting plate inside the main cavity, and one of the laser mirrors. This additional cavity made it possible to control also the energy of a pulse at the resonance frequency and to reduce (by no more than 50 ns) the delay time of this pulse (relative to a discharge-current pulse), compared with the delay times of pulses at other frequencies. The results obtained were used to propose schemes for two-frequency isotopically selective dissociation of molecules inside a nonselective cavity of a TEA CO₂ laser (without a diffraction grating).