NONLOCAL EFFECTS ON THE OPTICAL-RESPONSE OF A ROUGH-SURFACE

The complete optical response of deterministic rough surfaces in the presence of spatial dispersion has been studied theoretically. One-dimensional roughness with TM polarization for the incident, reflected and transmitted light has been considered. We present solution based on the Rayleigh-Fano method, which gives all amplitudes of the diffracted partial waves. The longitudinal mode has been included by an additional boundary condition. Nonlocal reflectivities for Ag are calculated numerically as functions of frequency, angle of incidence and wavevector component parallel to the surface using the hydrodynamic dielectric function and the Johnson and Christy dielectric constant. A significant shift in the values of the aforementioned variables with respect to local case has been obtained which is evident not only for microroughness but also for large grating period. We show how it would appear in experimental reflectivity expectra.