Expansion Ratio Influence on Population Inversion in CO2/Ar CW Gasdynamic Lasers Operating at Various Transitions within Coupled Upsilon 1 and Upsilon 2 Modes of CO2

摘要

The relation between the stagnation temperature and the expansion end temperature and the population inversion formed by rapid expansion for various transitions among vibrational levels in coupled upsilon 1 and 2 modes of CO2 is discussed. The sample relations for a CO2/Ar mixture expanding in a logarithmic profile supersonic nozzle were derived. The results show that for different lines of the spectrum the relation between the ratio of expansion and the population inversion is different, thus allowing the possibility to tune CW gasdynamic laser output beam spectra by chosing the initial and/or final temperature of the expanded gas mixture.