ABSTRACT
Development in the field of optical biosensors received significant impetus from the need of improvement in the area of laboratory-based immunodiagnostics. Optical techniques seemed an obvious choice for this area, since refractive index is one of the few physical parameters that vary upon the formation of an immune complex [1]. While interest in diffraction phenomena and the curious absorption anomalies of metallized optical diffraction gratings in particular dates back to the turn of the century, more systematic theoretical work in the field did not start until the 1950s, with the major advances published again much later [2-5].
