Water Vapor Absorption Measurements using a Line Tunable Deuterium Fluoride Laser,
Abstract
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1976
- Accession Number
- ADA026165
Entities
People
- Charles W. Bruce
- Kenneth O. White
- Wendell R. Watkins
Organizations
- Atmospheric Sciences Laboratory