SPR SENSOR DEVICE WITH NANOSTRUCTURE

A sensor device comprises a dielectric substrate (52); and a metal layer (53) on the substrate (52) with at least one array of cavities (54) therein and adapted to support L- SPR, each of the cavities (54) in the metal layer (53) having an opening (56) and a closed bottom (58) and widening from opening to bottom. A bed of dielectric material (62) is provided over the bottom (58) of each cavity (54) to reduce its apparent depth, the bed surface (62) being functionalized to bind to receptor moieties (64). This sensor device is particularly designed for SPR detection, but can be used in other detection techniques.