The Absorption of Laser Radiation Along Atmospheric Slant Paths

Abstract

The absorption of laser radiation along atmospheric slant paths is calculated when Lambert’s law is valid. Illustrative results are given for absorbing gases which are distributed uniformly throughout the atmosphere and when the temperature variation of the line intensities and half-width can be neglected. These results are then generalized to include cases of nonuniformly distributed gases with a temperature variation along the path. The effect of the overlapping of spectral lines is studied through the use of the Elsasser model. Finally, it is shown that large differences in the absorptance may occur between corresponding frequencies in the red and violet wings when there is a shift in the position of the line center with pressure. This line shift could ideally be studied with laser sources.