Tuning and sensitivity enhancement of surface plasmon resonance sensor

The performance of a surface plasmon resonance (SPR) sensor depends on its design properties. In this paper, we described, both theoretically and experimentally, the role of the prism material in sensor design. The analyses were carried out by employing three prisms of different refractive indices and the reflection spectra were studied under the angular interrogation mode. The results proved that the choice of prism material can tailor the resonance condition and thus can effectively tune the working region of the sensor. Also, the experimental value of angular sensitivity increased from 94.46°/RIU to 204.41°/RIU on changing the refractive index of the prism from 1.597 to 1.456, without changing the other parameters. The variation of the angular sensitivity was in accordance with the analytical and numerical results. The dynamic range decreased and the full width at half maximum (FWHM) of the reflection spectra increased as the refractive index of the prism was lowered, thereby affecting the sensor's performance.