The spectral power output of the transition of 10.6 um band is obtained in $CW-CO_2$ laser by rotating the grating which is used as a laser resonator. The output power of each transition is measured for different gas mixing ratio and for different discharge current. The relative spectral power distribution obtained as a function of rotational quantum number J is compared with the values obtained from the theoretical calculations for determination of the rotational temperature $T_R$ and population ratio of the vibrational states (00˚1) and (10˚0, 02˚0)I. The obtained values show that rotational temperature $T_R$ decreases as hellium contents increases and population ratio has its maximum values of 1.3 when the gas mixing ratio is $CO_2: N_2:He = 1:1:9$.
The mechanism of operation of the Hybrid-$CO_2$ laser which has both a TEA and CW discharge tube inside a resonator is discussed with reference to numerical solutions of rate equation. As the power in CW section increases, the calculated output power in Hybrid-$CO_2$ laser decreases and its radiation rapidly grows to give a pulse. The experimental results are nearly in accordance with the theoretical output power characteristics.
