Surface plasmon resonance-based optical sensor using a thin layer of plasma

Abstract

We propose a surface plasmon resonance (SPR) biosensor that consists of six layers: glass prism (SF 10), chromium, metal, molybdenum disulphide, graphene, and sensing medium. A seventh layer is added between the glass prism and the chromium layer, which is a gap filled with plasma as a dielectric material. The plasma layer is expected to carry the amenity of the graphene optical characteristics and absorption ability. It is also expected to improve sensitivity of the SPR structure. The numerical calculations show that the sensitivity of the sensor is 76.11 deg/RIU (refractive index unit); without the plasma layer, it can be improved to 103 deg/RIU in the presence of 25 and 35 nm thick plasma and silver layers, respectively. The structure parameters are optimized with respect to the sensitivity. The proposed sensor can potentially be used for biological purposes.