Characteristics of the changes in the refractive index due to interaction of a radiation pulse with an inverted medium

An allowance is made of the influence of various processes on the dynamics of the changes in the refractive index during amplification of radiation in a CO₂ – N₂ inverted medium. It is shown that a transient focusing lens can form as a result of the amplification of the radiation by resonant interaction with the R branch of the 00⁰1 → 10⁰0 transition in the CO₂ molecule. It is demonstrated that in cases of practical interest the macrotransport processes, associated with a nonequilibrium distribution of the energy between the vibrational degrees of freedom of the CO₂ and N₂ molecules have only a slight influence on the refractive index.