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

The complete optical response of deterministic rough surfaces in the p resence of spatial dispersion has been studied theoretically. One-dime nsional roughness with TM polarization for the incident, reflected and transmitted light has been considered. We present solution based on t he Rayleigh-Fano method, which gives all amplitudes of the diffracted partial waves. The longitudinal mode has been included by an additiona l boundary condition. Nonlocal reflectivities for Ag are calculated nu merically as functions of frequency, angle of incidence and wavevector component parallel to the surface using the hydrodynamic dielectric f unction and the Johnson and Christy dielectric constant. A significant shift in the values of the aforementioned variables with respect to l ocal case has been obtained which is evident not only for microroughne ss but also for large grating period. We show how it would appear in e xperimental reflectivity expectra.