<title>Coherent light backscattering by refractive turbulence in the atmosphere</title>

Abstract

A sharp peak is shown theoretically to exist in angular distribution oflight scattered by a layer of random medium with weak refractive index fluctuations in the Vicinity of backward direction. The peak width may be estimated by the ratio of incident radiation wavelength and the turbulence correlation scale. The effect is found to be fonned by coherent addition of contributions from elementary layers, and may be considered as an analog to "weak photon localization" phenomena in random media.When the width of scattering layer is large enough compared with the correlation scale of refractive index inhomogeneities, the differential scattering cross-section is composed by the "coherent" component and "incoherent" one, obtained earlier by V.I.Tatarski. In the case of visible or JR radiation (in contrast to microwaves) the "coherent" constituent determines the scattering for large angles close to 1800. Quantitative estimates show the backscattering by turbulent layers in atmosphere to produce noticeable contributions to signal registered in remote sensing monostatic lidar experiments, and thus the effect under consideration has to be taken into account when interpretation of laser remote sounding data is carried out. 0-8194-1642-8/94/$6.O0 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 10/10/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx SPIE Vol. 2372/133 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 10/10/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx