Atmospheric laser beam propagation

Laser beam propagation is modified by absorption, by scattering and by turbulence. Absorption in the atmosphere is brought about by molecular constituants. The absorption by scattering depends on Rayleigh scattering and Mie scattering; Rayleigh scattering can be neglected for wavelengths longer than 0,5 microns. Mie scattering is related to the dimensions of the particles; the attenuation of hazes and selective fogs decreases when the wavelength increases. The effects of turbulence on laser beam propagation are beam spreading, beam deviation, amplitude and phase variations whose consequences are scintillation and coherence losses; those effects are more important for short wavelengths than for long wavelengths.