Interaction of electromagnetic waves with periodic gratings: Enhanced fields and the reflectivity

Abstract

We present results of calculations of the reflectivity of diffraction gratings of sawtooth profile, and of electric fields near such gratings. We employ a method based on the use of the extinction theorem, and the grating amplitude is not assumed small. This approach also allows one to calculate the electric fields within the selvedge region of the grating. We place emphasis on frequency regimes where the grating couples an incoming photon to a surface polariton on the grating. The implications of our results for the study of optical interactions on surfaces are discussed.