Effects of Atmospheric Water Vapor Absorption on Infrared Laser Propagation in the 5 Micrometer Band.

摘要

The purpose of this study was to gather temperature dependent nitrogen broadened water vapor data at infrared frequencies of 1941.0952/cm, 1943.8624/cm, and 1949.2495/cm. This data is to be used to improve on the temperature characteristics of a far wing line shape model developed by M.E. Thomas and R.J. Nordstrom at the Ohio State University. In addition, the study investigated this 5.15 micrometer region for on-line/off-line resonance pairs for possible remote sensing of water vapor by DIAL techniques. The probe frequencies of 1941.0952/cm, 1943.8624/cm and 1949.2495/cm were generated by frequency doubling with a CdGeAs2 crystal pumped by a C02 laser lasing on the R(12), R(14) and R(18) lines of the (00 deg 1-10 deg 0) band, respectively. Due to experimental uncertainties in the data obtained during the study, only a general temperature characteristic of the absorption for the investigated laser lines was obtained. The data did show agreement with the far wing line shape model to a first order approximation; however, the study concluded that more accurate data is needed before a more detailed analysis can be made of the absorption versus temperature for these lines. A possible on-line/off-line pair for DIAL applications was also found-the doubled C02 R(18) and R(20) lines, respectively. (Author)