Chemical Lasers

Abstract

Chemical lasers typically integrate chemical delivery systems, a supersonic mixing nozzle, and an optical resonator to produce a high power beam of coherent light. An exothermic chemical reaction can produce the population inversion required for light amplification. The hydrogen fluoride chemical laser uses a population inversion between vibrational levels to generate laser beams with powers exceeding 1 MW at wavelengths near 2.7 μm. The chemical oxygen–iodine laser (COIL) uses a two‐phase reaction to produce electronically excited molecular oxygen and subsequent energy transfer to atomic iodine to lase at 1.315 μm. Chemical laser efficiency may be characterized by the mass flow rate required to generate a specified power, with values of greater than 100 kJ/kg achievable. Nozzle flux, or laser power per unit area of the mixing nozzle throat, is key to device size, with values of greater than 100 kW/cm 2 . The Airborne Laser mounted a high‐power COIL on a Boeing 747 to destroy theater missiles in the boost phase with a successful demonstration in 2010. The space‐based laser (SBL) was one of the most technologically aggressive elements of the Strategic Defense Initiative (SDI) and the only boost phase ballistic missile defense system with global coverage.