Continuous wave (cw) hf overtone chemical laser

Lee H. Sentman; David L. Carroll; Panagiotis T. Theodoropoulos; John W. Otto; Shawn J. Gordon

doi:10.1117/12.204939

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31 March 1995 Continuous wave (cw) hf overtone chemical laser

Lee H. Sentman, David L. Carroll, Panagiotis T. Theodoropoulos, John W. Otto, Shawn J. Gordon

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Proceedings Volume 2502, Gas Flow and Chemical Lasers: Tenth International Symposium; (1995) https://doi.org/10.1117/12.204939
Event: Gas Flow and Chemical Lasers: Tenth International Symposium, 1994, Friedrichshafen, Germany

Abstract

Overtone performance of the cw HF chemical laser was optimized by the same flow rates that optimized fundamental performance. When the absorption/scattering losses of the mirrors were taken into account, an overtone efficiency of 70 - 90% was achieved. The overtone efficiency was a strong function of medium saturation. There was no significant change in overtone power and efficiency as the mode volume increased. However, there was an increase in the number of lasing lines and a shift to higher rotational lines. Overtone performance was as sensitive to cavity pressure as fundamental performance. Rigrod theory showed that a higher medium saturation yields a higher overall overtone efficiency, but does not necessarily yield a higher measurable power (power in the bucket). For low absorption/scattering loss overtone mirrors and a 5% penalty in outcoupled power, the intracavity flux and hence the mirror loading may be reduced by more than a factor of two when the gain length is long enough to well saturate the medium. For the UIUC overtone laser which has an extensive data base with well characterized mirrors for which the Rigrod parameters g₀ and I_sat were firmly established, the accuracy to which the reflectivities of high reflectivity overtone mirrors can be deduced using measured mirror transmissivities, measured outcoupled power and Rigrod theory is approximately +/- 0.07%.

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Lee H. Sentman, David L. Carroll, Panagiotis T. Theodoropoulos, John W. Otto, and Shawn J. Gordon "Continuous wave (cw) hf overtone chemical laser", Proc. SPIE 2502, Gas Flow and Chemical Lasers: Tenth International Symposium, (31 March 1995); https://doi.org/10.1117/12.204939

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