A parametric study of the output of the optically pumped continuous wave CF/sub 4/ laser

A parametric study of laser output versus CF/sub 4/ pressure and temperature was performed and correlated with a model for the gain in the system, which includes the relevant relaxation processes. Lasing in CF/sub 4/ was observed at temperatures below 170 K. Cooling the CF/sub 4/ gas, the output power of the laser increased from 3 mW at 142 K to 5 mW at 113 K, when 4% of the radiation was coupled out. Chopping the pump, the 16- mu m signal consisted of a peak decaying in approximately 2 ms, superimposed on a CW background. This decay is caused by the slow relaxation in the CF/sub 4/ laser, resulting in filling of the lower laser level. For the CW CF/sub 4/ laser, vibrational relaxation from the laser lower level is even slower than diffusion to the cold cell walls. To increase the relaxation rate, HD was added. In this molecule, the J=1 to 3 rotational transition at 447 cm/sup -1/ is almost resonant with the nu /sub 2/ vibration in CF/sub 4/. Maximum CW output was increased by 25% in a mixture containing 10% HD. At the same time, the lasing pressure range was extended.<
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