Water Vapor Absorption Measurements using a Line Tunable Deuterium Fluoride Laser,
ARMY ELECTRONICS COMMAND WHITE SANDS MISSILE RANGE N MEX ATMOSPHERIC SCIENCES LAB
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The design and performance of Army electro-optical systems depend on accurate and detailed knowledge of the atmospheric transmission in the 3-5 micrometers spectral region. This study concerns DF laser propagation 3.5-4.1 micrometers. The results of this work have important implications for laser as well as broadband infrared systems operating in the 3-5 micrometer atmospheric window. Systems which fall into this class are DF high-energy lasers, low-power lasers for target designation, infrared seekers, and infrared imaging scanners. The two primary sources of atmospheric attenuation of DF laser wavelengths are molecular absorption and aerosol attenuation both scattering and absorption. For most meteorological conditions in which haze or fog are not present, molecular absorption is significantly greater than aerosol attenuation. For high-energy laser HEL system modeling, the molecular absorption contribution is particularly important because the energy absorbed quickly heats the atmosphere along the laser path, resulting in density variations and causing distortion or thermal blooming of the laser beam. Aerosol attenuation is less important for thermal blooming because the majority of aerosol attenuation results from scattering of energy out of the beam where it cannot cause blooming.
- Atmospheric Physics
- Lasers and Masers
- Atomic and Molecular Physics and Spectroscopy