Atmospheric attenuation of the HF and DF laser radiation

The atmospheric attenuation properties of the HF and DF laser transmission. The absorption of watervapor in the atmosphere is very weak to the DF spectral lines, while those of the watervapor and CO2 are very strong to the HF spectral lines. The atmospheric attenuations of the HF and DF spectral lines are calculated based on the latest HITRAN 96 database and the meterologic data for different districts in China. For the selected HF spectral lines, the maximum absorption coefficient of watervapor in Hefei area is up to 10km-1, that of CO2 is up to 10-4 or 10-3km-1 and that of P2(8) line is the weakest. The maximum absorption coefficient of watervapor to DF spectral lines is 2 orders in the magnitude lower than that to HF spectral lines and attenuates drastically with the increase of