Atmospheric Attenuation of HF and DF Laser Radiation

Book excerpt: With the development of HF and DF lasers having emission lines in the range from 2800 to 3700/cm−1 (HF) and 2000 to 2750/cm−1 (DF), it is of importance to establish which of the more than 100 lines can be transmitted through a variety of atmospheric paths. The spectral region of HF emission spans a very important water vapor absorption band and, in addition, there is strong absorption by CO2 and weaker absorption by ozone and methane. The spectral region of DF emission covers the very strong 4.3 micrometer CO2 absorption band and weaker absorption by N2O and HDO at higher frequencies (low DF vibrational transitions). There is some weak ozone absorption also in the region of DF emission. Absorption lines associated with all of these molecules were included in the calculation of synthetic spectra covering the region of HF and DF emission. After limiting the number of emission lines to be considered in detail according to a criterion based on atmospheric attenuation, a series of tables was constructed providing quantitative attenuation information for each of 97 laser lines and for 10 different atmospheric models. Data based on two different aerosol scattering models are included in these tables.