Resonance asymmetry and frequency shifts of stabilized CO2/OsO4 laser under conditions of self-focusing of radiation in nonlinearly absorbing medium

An experimental investigation was made of the asymmetry of a resonance of saturated absorption and of frequency shifts exhibited by a stabilized CO₂/OsO₄ laser as a function of the following: the conditions during photorecording of the output beam in an external nonlinearly absorbing cell, the ¹⁹²OsO₄ vapor pressure, and the radiation intensity. A quantitative characteristic was introduced to describe the resonance asymmetry. A study was made of the radial distribution of the resonance asymmetry of a Gaussian laser beam at the exit from the absorption cell. A linear relationship was found between the resonance asymmetry and the shift of the laser frequency. A dispersive profile acquired by the resonance and the resultant resonance asymmetry together with the shift of the stabilized frequency were described by a theoretical model based on self-focusing of a Gaussian optical beam in a nonlinearly absorbing medium.