ANALYTICAL AND COMPUTATIONAL MODELS FOR A LASER-RADIATION FIELD SCATTERED BY ROUGH SURFACES

A 2-D spectral formalism using a superposition in plane waves for scat tered and transmitted laser fields, to find solutions for Helmholtz eq uations, is described. The formalism is used to obtain the angular spe ctral amplitudes (ASA) of the laser radiation field scattered by rough surfaces. The equations are solved by numerical computation. To simul ate the scattering from a real rough surface, various deterministic pr ofiles, combinations of them, and a random rough surface with Gaussian statistics are used. The latter is generated in an original manner, b y using a filter function to transform the uniformly distributed rando m numbers, generated by computer, into a set of random numbers with Ga ussian statistics. The formalism is tested by applying it to laser rad iation scattered by a flat surface and the results are as expected. Ei ght different surfaces with the same average height and the same root mean square (rms) roughness are considered and they are supposed to be illuminated at various incidence angles by laser radiation with a kno wn wavelength, For each surface, the ASA versus scattering angle depen dence, corresponding to five angles of incidence, is represented. (C) 1996 Society of Photo-Optical Instrumentation Engineers.