The dependence of the light field of a limited radiation beam in a turbid medium on the form of the forward-scattering index is investigated in the small-angle-scattering approximation. The contribution of small-angle scattering to the attenuation index of the separate spatial harmonics of the beam's initial radiance distribution is analyzed. Calculations are carried out with the volume scattering functions experimentally measured by Petzold for three types of sea water (clear ocean, coastal ocean, and turbid harbor) and Dolin's model index, as well as in the small-angle diffusion approximation. A discussion is given of how the “small-angle” scattering index affects the irradiance-attenuation index and the size of the light-beam cross section in the problem of remote laser probing of the ocean.
© 2010 Optical Society of AmericaPDF Article