Refinement of a vibrational-temperature model for describing the lasing characteristics of a short-pulse CO2-N2-He laser

A theoretical study of the relaxation of CO2 and N2 at high pumping levels (Q/P not less than 0.2-0.3 J/cu cm) is used to refine a kinetic model for the CO2-N2-He laser active medium, in which the vibrational-temperature approximation is used to determine populations of N2 and CO2 levels. In the proposed model, the population kinetics of the vibrational levels of N2 oscillators and the antisymmetric CO2 vibrational mode are calculated on the basis of kinetic equations which incorporate v-v and v-T exchange in the anharmonic approximation. Theoretical results are compared with experimental data for different pumping levels, and the comparison is used to explain the systematic error associated with the vibrational-temperature approximation.