On the Performance of Graphene-Based D-Shaped Photonic Crystal Fibre Biosensor Using Surface Plasmon Resonance

We propose a D-shaped photonic crystal fibre-based surface plasmon resonance sensor considering graphene on silver for sensing of refractive index of analyte and thickness of biolayer. The different structural and material parameters associated with sensor have been optimised. Graphene not only helps in adsorption of biomolecules due to π-π stacking interaction but at the same time prevents oxidation of metal-like silver. Numerical simulation shows that amplitude sensitivity of the proposed structure for chemical analytes is 216 RIU−1 (refractive index unit) with a resolution of 4.6 × 10−5 RIU while the wavelength sensitivity of the proposed sensor is found to be as high as 3700 nm RIU−1 with resolution of 2.7 × 10−5 RIU. Further, the proposed sensor can also be used for the detection of biolayer thickness in both amplitude and wavelength interrogations. An amplitude sensitivity of 0.26 nm−1 with resolution of 39 pm and wavelength sensitivity of 2 nm nm−1 with resolution of 50 pm is achievable for the determination of biolayer thickness. The proposed structure is easy to use as there is no need of filling of voids, and the analytes can be placed easily on the flat surface of photonic crystal fibre (PCF).