PhysicsLetters A 183 ( 1993) 253-256 North-Holland PHYSICS LETTERS A Some aspects of electromagnetic wave scattering from a nonabsorbing rough surface V. Freilikher and I. Yurkevich Jack and PearlResnick Institute of Advanced Technology, Department of Physics, Bar-llan University, Ramat-Gan 52900, Israel Received 3 May 1993;revised manuscript received 10 August 1993;acceptedfor publication 16 September 1993 Communicatedby A. Lagendijk The scattered intensity angle distribution is studied for electromagnetic waves incident on a slightly rough dielectric surface. New results valid when there is no real absorption on the interface are obtained. It is shown that the shape of the peak near the retroreflection direction exhibits a strong dependence on the geometryof the surface. The angular correlation function of the amplitudes of two waveswith different incident angles is calculated. The possibilityto use the "memoryeffect" for the determi- nation of the degreeof homogeneity of a random surface is discussed. The rapid progress in microwave technology and computer facilities have enabled the creation of microwave remote sensing systems capable of solving a wide range of scientific and practical problems in investigations of environments. For the effective functioning of these systems the development of remote sensing principles, based on the modem theories of surface and volume scattering, is absolutely necessary. In this connection one of the most important problems is the investigation of backscattering enhancement (weak localization), whose discovery leads to the imperative necessity of revising the fundamental concepts of radiolocation and remote sensing, both of which are based on the measurements and investigations of a signal scattered in the direction opposite to that of the incident wave. Thorough experimental and numerical studies of the backscattered enhancement have been carried out in optics for very rough surfaces [ 1-3 ]. Although there is no exhaustive analytical theory, it is clear that the phys- ical nature of the phenomena in this case is similar to that of the phenomena in a volume scattering system: it is caused by the interference of multiply scattered waves, which are provided by the reflections of beams from different randomly oriented parts of the surface. For slightly rough surfaces a theory was developed [4-7], but considering that the scattering from polaritons to outgoing volume waves was disregarded, the results obtained are valid only in the case of very strong ab- sorption in the lower media, and diverge when the absorption mean free path labs tends to infinity. In ref. [ 8 ] this drawback has been overcome, and formulae valid for nonabsorbing media were obtained for the intensity of scalar waves scattered from a surface with random impedance. In this paper the intensity distribution of electromagnetic waves scattered from a rough dielectric interface is studied from the point of view of the applications to the surface inverse problem. The distinctive feature of the electromagnetic field is the presence of a scattered cross-polarized component in which the enhanced back- scattered peak is more pronounced (and hence it is more easily measurable) than in the scalar case. This stems from the fact that if the vectors of the incident and scattered waves lie in the same plane, the amplitude of the cross-polarized component itself is proportional to the second order diagrams, which means that an enhanced backscattered peak exists in leading order and is not screened by the single-scattered field. The formulae for the depolarized component scattering indicatrix near the antispecular direction are ob- tained. It is shown that the form of the enhanced backscattered peak is strongly dependent on the surface di- 0375-9601/93/$ 06.00 © 1993 Elsevier SciencePublishers B.V. All fights reserved. 253