Effect of Foreign Gas onν₃-Mode Vibrational Temperature for Regular and Sequence Band Transitions in Waveguide CO₂Lasers

From small signal gain measurements for the CO 2 regular and sequence band transitions in a waveguide laser medium, the foreign gas effect on the ν 3 -mode vibrational temperature is investigated and compared with that in a large-bore flow tube, ordinary laser medium. The vibrational temperature in the waveguide is apparently higher than that in a large-bore flow tube, ordinary laser at any partial pressure of foreign gas in the gas mixture. The vibrational temperature decreases with increasing foreign gas N 2 partial pressure, whereas it increases with increasing He partial pressure. The total and partial derivatives of the vibrational temperature for the variables of the foreign gas pressure and the injected power are experimentally obtained and discussed.