Traditionally, high-energy lasers have used optics which have been actively cooled, primarily with temperature-conditioned, deionized water. The Ballistic Missile Defense Organization (BMDO) has successfully developed Very Low Absorptance (VLA) coatings for optics for Hydrogen-Fluoride (HF) lasers. These coatings have produced the next generation in high energy optics: uncooled optics. This paper addresses the successful transfer of this technology to Deuterium-Fluoride (DF) lasers. Both analytical predictions and experimental results are presented.
Large aperture single crystal silicon turning flat mirrors provide a new method of high energy laser beam sampling for optical performance diagnostic measurements. This new sampling technique has been successfully implemented on the Alpha Laser Optimization program where transmitted beams through two, uncooled silicon mirrors have been used to measure total energy, instantaneous power, spectral content, and beam jitter. The accuracy of these measurements has been confirmed by independent measurements of these same parameters, and the results fall within expected error bars.
Characterization of atmospheric turbulence and thermal blooming for high energy laser propagation has been conducted for the Scaled Atmospheric Blooming Experiment (SABLE) under controlled experimental conditions. To enhance thermal blooming with a high brightness, moderate power laser beam, a hydrogen fluoride (HF) chemical laser, producing six major lines, P1(7), P1(8), P1(9), P2(7), P2(8), and P2(9), was utilized. This paper summarizes design options and the design and operation of an X-folding scheme and the resulting quad-pass resonator (QPR), which produced a spectrum shift of 2 J-lines, a near-field irradiance distribution that was more uniform along the flow direction, had less line-to-line variation in near-field irradiance distribution, and produced twice the far-field power after atmospheric propagation, when compared to a more conventional double-pass resonator (DPR).