Surface plasmon interferometer in silicon-on-insulator: novel concept for an integrated biosensor.

We propose a novel configuration for a highly integrated and highly sensitive optical biosensor. The basic element of the sensor is a surface plasmon interferometer consisting of a thin layer of gold embedded in a silicon membrane. We investigate the performance of the sensor by simulation using eigenmode expansion. We calculate that refractive index changes in the order of 10(-6) RIU should be easily detectable for a component of length 10 microm. Moreover, we illustrate that the operation wavelength of the sensor can be easily tuned to a desired wavelength for a wide range of environmental refractive indices, making our device suitable for chemo- and biosensing.