Output power enhancement of optical pumped gas waveguide terahertz laser by promoting vibrational de-excitation

Based on rate equation and vibration relaxation theory, the paper analyze theoretically the enhancement of THz laser output power due to vibration de-excite rate of the active gas considering buffer gas ratio and waveguide core diameter. The results show that the method of adding 1:1 buffer gas or appropriately reducing the waveguide core diameter can improve work material saturated absorption intensity, THz laser small signal gain coefficient, THz laser output power and decrease the THz absorption of excited work material at the same time. Considering the two factors at the same time, the above results are better than those with only one factor, and the output power improved by 18%.