Dependences of the gain of cataphoretic lasers on helium pressure and discharge-tube diameter

The known mechanisms of the pumping of laser levels are used in calculations of the dependences of the gains of Cd–He, Se–He, and Sb–He cataphoretic lasers on the pressure of helium and on the discharge-tube diameter. The calculations are compared with the experimental results. It is found that when the helium pressure is increased, these dependences become strongly affected by a reduction in the optimal concentrations of the active substance in the discharge (Cd–He and Se–He lasers) and by a reduction in the electron temperature (Sb–He laser). The observed rise of the gain on reduction of the discharge-tube diameter is mainly due to an increase in the optimal concentration of the active substance.