Water Vapor Absorption Coefficients at HF Laser Wavelengths. Part I. Atmospheric Conditions Corresponding to Altitudes up to 7 km.
Research and development technical rept.,
ARMY ELECTRONICS RESEARCH AND DEVELOPMENT COMMAND WSMR NM ATMOSPHERIC SCIENCES LAB
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Water vapor absorption measurements are reported at nine HF laser wavelengths ranging from P sub 3-2 5 at 3418.1600cm to P sub 1-0 4 at 3788.2253cm. The results were obtained with a temperature controlled longpath absorption cell and a path differencing technique with path differences ranging from 8 to 152 m. Cell temperatures ranging from -18 to 25 C were used. Pure water vapor as well as air N2O2 broadened water vapor absorptions were measured for pressures ranging from less than 1 torr to 764 torr. Limited data on O2 broadened water vapor absorption as well as pure and air broadened CO2 absorption are presented. In general the air broadened water vapor results show more absorption than predicted and imply a super Lorentz or Voigt line shape. The pure O2 broadened water vapor absorption is less than the air broadened absorption. New self- and foreign-broadening coefficients are obtained. Finally, the limited CO2 absorption observed shows good agreement with theoretical predictions. These results will allow more accurate modelling of atmospheric transmission for EO and HEL applications. Author
- Atmospheric Physics
- Lasers and Masers