CONTINUOUS-WAVE HYDROGEN-FLUORIDE OVERTONE LASING SATURATION EFFECTS ON FUNDAMENTAL GAIN SUPPRESSION

A new technique that uses a multiline probe beam to measure the gain o n several lines simultaneously was developed. This new technique was u sed to measure the gains of the fundamental lines P-1(4-9) and P-2(4-9 ) while lasing on the overtone, for three levels of medium saturation. For relatively high-medium saturation, obtained with 99.7/99.7% refle ctive mirrors, the gains of the low J lines P-1(4-6) and P-2(4-6) were suppressed 41-96%; the gains of the high J lines P-1(7-9) and P-2(7-9 ) were suppressed 3-44%. The 1 --> 0 lines were suppressed more than t he 2 --> 1 lines. The maximum suppression occurred between 2 and 6 mm downstream from the nozzle exit plane, near the center of the 9-mm ove rtone beam. The suppression obtained with 99.8/99.86% reflective mirro rs, which resulted in 55% larger intracavity flux, was essentially the same as that obtained with the 99.7/99.7% mirrors. For low-medium sat uration, obtained with 98.0/99.7% reflective mirrors, there was essent ially no suppression of the fundamental gains.