Experimental Verification Of The Slow Dither Concept For Thermal Blooming Compensation

Bruce J. Pierce; James E. Harvey; Raymond C. Dymale; Julian S. Nichols

doi:10.1117/12.957949

19 December 1979 Experimental Verification Of The Slow Dither Concept For Thermal Blooming Compensation

Bruce J. Pierce, James E. Harvey, Raymond C. Dymale, Julian S. Nichols

Proceedings Volume 0195, Atmospheric Effects on Radiative Transfer; (1979) https://doi.org/10.1117/12.957949
Event: 23rd Annual Technical Symposium, 1979, San Diego, United States

Abstract

A multidither adaptive optical technique using dither frequencies below that of the atmosphere's characteristic response has been proposed for thermal blooming compensation. When such low dither frequencies are used, the atmosphere, which is coupled to the high-energy laser (HEL) beam through the absorption processes that create blooming, is thermally driven at the dither frequency. The modulated thermal radiation returning from the hot spot (created at the target by the high-energy beam) is optimized by using a hill-climbing servo system, and through reciprocity the HEL target irradiance is correspondingly optimized. Computer analyses of the slow dither concept predict convergence to an optimum target irradiance even when strong thermal blooming conditions are present. We have established a laboratory facility for the evaluation of adaptive optical compensation. A low-speed wind tunnel containing a small concentration of Freon 12 is used to simulate a wide variety of realistic blooming scenarios. In this paper we report some results of the first experimental investigation of the slow dither concept.

Citation Download Citation

Bruce J. Pierce, James E. Harvey, Raymond C. Dymale, and Julian S. Nichols "Experimental Verification Of The Slow Dither Concept For Thermal Blooming Compensation", Proc. SPIE 0195, Atmospheric Effects on Radiative Transfer, (19 December 1979); https://doi.org/10.1117/12.957949

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