Chalcogenide glass prism based SPR sensor with Ag-Au bimetallic nanoparticle alloy in infrared wavelength region

A chalcogenide prism based surface plasmon resonance sensor with Ag-Au bimetallic alloy nanoparticles is proposed. The plasmonic structure based on (chalcogenide) sulfide glass Ge20Ga5Sb10S65, commonly known as 2S2G, allows for a wide range of sensing applications in the infrared wavelength region. Theoretical calculations are carried out to design a device providing an accurate sensing in the infrared range by exploiting the unique optical properties of 2S2G chalcogenide glass. The angular interrogation method is used to analyze the sensor's performance in terms of its intrinsic sensitivity. The intrinsic sensitivity takes both angular shift as well as the angular width of the SPR curve into account. The adequate values of crucial design parameters are predicted in order to achieve the best possible sensing performance. The proposed sensor can be very useful for chemical and bio-sensing applications in the infrared due to the large operating window of chalcogenide materials.