HF Chemical Lasers Ignited by CO sub 2 -Laser Irradiation

摘要

A pulsed CO sub 2 laser was used to ignite mixtures of SF sub 6 :H sub 2 and S sub 2 F sub 10 :H sub 2 . The chemical reactions initiated by the CO sub 2 laser produce vibrationally-excited HF which were observed to lase when an optical resonator was constructed around the reaction cell. The HF-lasing performance of these gas mixtures as a function of mixture ratio, pressure, and several CO sub 2 -laser parameters (frequency, fuence, and pulse duration) are compared. Under comparable conditions, the HF-laser output for S sub 2 F sub 10 :H sub 2 mixtures was approx. 6 times greater than that for SF sub 6 :H sub 2 mixtures. Two results were observed that are not fully understood at present: First, the HF-laser output for S sub 2 F sub 10 :H sub 2 mixtures increased linearly with CO sub 2 -laser fluence, reached a maximum value, and then decreased - this decrease may be due to excessive heating of the gases. Second, variations in CO sub 2 -laser frequency indicated that the frequency for maximum HF-laser energy from S sub 2 F sub 10 :H sub 2 mixtures was blue-shifted with respect to the peak absorption frequency for S sub 2 F sub 10 - this may be due to significant SF sub 5 absorption of the CO sub 2 -laser radiation. (ERA citation 06:011422)