Graphene/Au/SiC Optical Waveguide-Based Surface Plasmon Resonance Sensor for Chemical and Biomedical Sensing in Aqueous Medium

摘要

In chemical and biomedical sensing, identification and quantification of analytes in aqueous medium such as water, blood or other carriers are very important. It requires the core sensors to have the properties of low cost, high sensitivity, on-chip integration capability, etc. Various sensing methods have been developed such as prism coupler and grating coupler, etc. and among them, waveguide-based surface plasmon resonance (SPR) sensors, with sensitivity of the optical waveguide significantly improved by SPR, have been identified as a powerful tool for detection and quantitative characterization of chemical and biological species or biomolecular reactions in aqueous medium. For sensing in aqueous medium, the optical waveguide sensors are desirable to operate in the visible light wavelength to overcome the large absorption coefficient of water in the near infrared range. This high absorption coefficient causes optical energy in the near infrared incident light be absorbed by water rather than by the sensing medium. Conventional silicon (Si) is not the choice of material for such sensors due to the strong absorption below the wavelength of 1.1 μm due to its narrow bandgap (Eg=1.12 eV, 1.1 μm wavelength).