Gas lasers utilizing cascade transitions in linear triatomic molecules

Some characteristics of gas lasers utilizing cascade transitions in linear triatomic molecules are discussed. General operating conditions are determined for a pulsed cascade laser with an arbitrary method of excitation and a simple technique is described for the calculation of its maximum energy output. This approach is used to analyze some features and to give an estimate of the energy yield of three-frequency CO₂ lasers with thermal and electric pumping. Practical recommendations on the development of cascade lasers are given and specific methods of improving their efficiency are proposed. It is found that under typical conditions the average radiation power at the ~16 µ wavelength in cascade CO₂ lasers can reach 0.5–0.6 W/cm³ in gasdynamic lasers and ~4.5 W/cm³ in an electric-discharge laser with a supersonic gas flow rate.