Diffraction of bounded light beams on a surface with an arbitrary relief under conditions giving rise to Wood anomalies

An analytic theory is developed of diffraction of bounded light beams of any transverse shape on a surface with an arbitrary relief under conditions which induce the appearance of the Wood anomalies. An investigation is made of the influence of the width of the incident beam, and of the profile and depth of the surface relief on local fields near the surface and on suppression of specular reflection. An equivalent differential equation is obtained for the description of the excitation, lateral displacement, and attenuation of a surface electromagnetic wave propagating along the surface relief, and the conditions under which this equation is valid are identified.