Anomalous optical response of silicon tip-shaped metasurface

Anomalous optical response for the metasurface fabricated from silicon resonators is investigated. Resonators have form of 3D micro cones - tips that are covered by semicontinuous silver film. Thus prepared metasurface exhibits anomalous optical response due to the excitation of metaldielectric resonances in visible and near IR spectral ranges. We investigate the effect of the “extraordinary” optical diffraction by tip-shaped metasurface. The multiple metal-dielectric resonances result in huge enhancement of the local electric field in-between metal particles placed on the surface of dielectric cones. SERS phenomenon is investigated by immobilization of DTNB (5,5'- dithio-bis-[2-nitrobenzoic acid]) molecules of on the metasurface.