Surface plasmon resonance-based gas sensor with chalcogenide glass and bimetallic alloy nanoparticle layer

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A theoretical model for a gas sensor based on chalcogenide prism and surface plasmon resonance is proposed. The metal layer consists of Ag–Au alloy nanoparticles. The chalcogenide prism is made of sulfide glass Ge20Ga5Sb10S65, commonly known as 2S2G. The angular interrogation method is used to analyze the sensor’s performance in terms of its intrinsic sensitivity that takes into account both the angular shift as well as the angular width of plasmon resonance curve. The effect of operating wavelength along with the size and composition ratio of alloy nanoparticle is studied on sensor's performance. The sensor’s performance improves with an increase in nanoparticle size and silver fraction. Large operating wavelength is found to be useful for accurate gas sensing. Therefore, proposed sensor can be very useful for gaseous sensing in infrared due to large operating window of chalcogenide materials.