Possible self-oscillatory processes in the radiation field of a CO2 laser with a nonlinear absorbing element

A theoretical investigation is made of the dynamics of operation of a wide-aperture CO₂ laser containing an intracavity absorption cell with an SF₆ — NH₃ gas mixture. It is shown that one can select such parameters of the laser that the profile of its optical field is of self-oscillatory nature in a wide range of pressures of the active and nonlinear media and for various cavity dimensions. Self-wave generation is influenced mainly by the vibrational — vibrational exchange between nitrogen and CO₂ and by the vibrational — translational relaxation of the lower laser-active level of the CO₂ molecule. Each of these processes favours self-wave generation and, depending on the composition of the active medium, one or two self-wave systems can be observed. The results are obtained for situations attainable in electric-discharge and electron-beam-controlled discharge lasers.