The backscattering of a laser beam from a particulate medium is studied by means of the radiative transfer equation, taking into account the effect of multiple scattering. An analytical expression for the backscattered power is obtained. From this the widely used single scattered lidar equation is recovered as an asymptotic form. Numerical results are discussed for the case of laser power returned from an advective fog.
W. G. Tam, "Aerosol backscattering of a laser beam," Appl. Opt. 22, 2965-2969 (1983)