Si grating structure for surface plasmon resonance excitation by back-side normal incidence illumination

We propose a structure suitable for surface plasmon resonance (SPR) excitation with light incident on the back-side of the device, which has affinity with the semiconductor process. We constructed a diffraction grating on the top layer of a silicon-on-insulator wafer and completely embedded the grating in a polymer. According to a reflectance measurement, SPR could be efficiently excited, and its behavior presented consistency with the calculations. Since this structure is semiconductor fabrication based and allows elimination of both the prism and the light receiver commonly used in SPR experiments, it will contribute to realization of a thin one-chip SPR device. (author)