Integral plug-in RF module in a CO2 hybrid-waveguide laser: Its performance and overall evaluation

This work describes the performance of a compact “in-house built” radio–frequency (RF)-excited CO2 slab waveguide laser which has the innovation of having a plugged-in RF generator–amplifier module directly connected into the positive electrode of the laser head. The design circuit parameters include a matching circuit and a feed-through element as a whole. The overall laser performance takes into account the waveguide dimension (y-axis) as approximately one-tenth of the free space transverse dimension (x  -axis). The optical resonator is calculated to be in the regime of the negative branch for unstable confocal resonators, having focal lengths of f1=21.49cm and f2=19.39cm with geometrical amplification of 1.108. Optical output coupling mirror was set to ∼9.7%. The calculated waveguide length is 37.73 cm whilst the total resonator length was adjusted to 42 cm to allow coupling losses less than 1%. The laser operational efficiency was about 12% and the output beam quality of 1.13 which is close to the ideal Gaussian beam. The optical output power was accomplished by playing with different gas compositions to have a final optimized gas proportion of 1:1:2.7:0.3 correspondingly to CO2, N2, He and Xe as admixture.