Holographic gratings for 90% power-efficient excitation of optical surface waves

Abstract

A holographic method for the design of low-loss grating couplers for optical surface waves excitation has been proposed. For a particular example of excitation of a plasmon-polariton wave in a dielectric layer on metal, the coupling efficiency of the proposed volume holograms in the dielectric layer has been analyzed in comparison with optimized periodic gratings of vertical slits in the dielectric layer. It has been shown that the coupling efficiency of the holographic gratings can exceed 90% (−0.46dB) for the vertically incident exciting Gaussian beam. The coupling efficiency of optimized periodic gratings of vertical slits in the dielectric layer was considerably lower for the same system and exciting beam parameters. The proposed method is universal: it can be applied to develop holograms for excitation of various types of waveguide modes and surface waves within dielectric and metal-dielectric structures.