HYDROGEN-FLUORIDE OVERTONE CHEMICAL-LASER TECHNOLOGY

The Hydrogen Fluoride Overtone Chemical Laser Technology Program has exploited the technology base developed over the last two decades for hydrogen fluoride lasers and successfully demonstrated a short wavelength chemical laser. This technology development centers on overtone lasing of the hydrogen fluoride molecule to produce laser radiation at 1.33-mu-m rather than the conventional fundamental lasing at 2.8-mu-m. The overtone wavelength can lead to significant improvements in brightness potential as well as atmospheric propagation properties. The concept has matured from initial demonstrations at the 10 W scale to the currently demonstrated multikilowatt level. In the course of these test programs, it was necessary to develop new highly reflective coatings that permitted short wavelength lasing while completely suppressing lasing on the fundamental. This paper briefly reviews the performance of both discharge-driven and combustion-driven chemical laser devices and the optical configurations employed in the scalability steps. Appropriate diagnostics are discussed, including power, efficiency, spectra, and small signal gain.