Gain generator optimization for hydrogen fluoride overtone and fundamental chemical lasers

Abstract

The hydrogen fluoride (HF) chemical laser is the baseline concept for SDIO space based laser (SBL) weapons systems. Ground based tests at power levels appropriate for this application have been demonstrated. Because the brightness of a laser beam projected to the far field is inversely proportional to the square of the wavelength, shorter wavelengths are desirable to enhance brightness on target. Development of the HF overtone chemical laser ((lambda) equals 1.3 - 1.4 micrometers ) as a growth technology for SBL applications has proceeded rapidly during the past several years. This paper reviews the parametric characterization and optimization of the Hypersonic, Low-Temperature (HYLTE) nozzle concept for HF overtone and HF fundamental performance. The experiments utilize advanced multilayer dielectric coatings on uncooled silicon substrates. The experimental results reported include laser power, small signal gain, mode footprint, and spectral content. The design of a multiple nozzle HYLTE module as a building block to an advanced high power HF chemical laser device is presented. Design philosophy emphasizes traceability from an intermediate size linear module to a full scale cylindrical gain generator for SBL applications. The key issues addressed are power scalability, fabricability, regenerative cooling capability, and thermal/structural performance.