Investigation of the gain and emission spectrum of a TE laser utilizing a mixture of isotopically substituted carbon dioxide molecules

The results are presented of theoretical and experimental investigations of the gain and emission spectrum of a TE laser utilizing a mixture of isotopically substituted $^{12}CO_2$ and $^{13}CO_2$ molecules. It was found that, in a wide range of active-medium pressures ($p=100-3500$ Torr) and excitation levels ($T_3=1200-2400$ K), a gas mixture such the concentration of $^{13}CO_2(x_{13})$ and $^{12}CO_2(x_{12})$ molecules satisfied the condition $x_{13}/(x_{13}+x_{12})\gtrsim0,35-0,45$ emitted one or several lines in the wavelength range between 11.11 and 11.22 $\mu$ [between $P(16)$ and $P(26)$ in the $00^01-10^00$ band of the $^{13}CO_2$ molecule] in a laser with a nonselective resonator. The lasing efficiency was approximately equal to that for $^{12}CO_2$. The results of calculations were in good agreement with the experimental data.