Fibre-optic sensor based on surface plasmon resonance with Ag–Au alloy nanoparticle films

The design of a fibre optic surface plasmon resonance (SPR) sensor based on silver–gold alloy nanoparticle film is studied. The performance of the proposed sensor is theoretically analysed in terms of its signal-to-noise ratio (SNR) and sensitivity under different conditions related to the metal layer with silver and gold nanoparticles embedded together in layers to form a single alloy film. The effects of related parameters such as alloy composition ratio, metal nanoparticle size, and alloy film thickness are studied and the physical reasoning behind the results is given. A logical comparison is carried out between a previously proposed metal-host based fibre optic SPR sensor and the present one. The alloy based fibre optic SPR sensor is shown to have better performance than the metal-host based fibre optic SPR sensor.