Ultra-sensitive graphene–gold hybrid dual core photonic crystal fiber sensor based on surface plasmon resonance for bio-analyte detection

This research work deals with highly sensitive detection capabilities of dual core photonic crystal fiber (PhCF) biosensor. It works on the principal of surface plasmon resonance (SPR) and consisted of hybrid coatings of graphene and gold layers for efficient detection of low refractive index (RI) values ranging from 1. 30 to 1. 39 in steps of 0. 01 of bio-analytes. This design is integration of the superior plasmonic properties of gold with an exceptionally high absorptive and conductivity properties of graphene for improving the light–matter interaction, in addition to signal stability. The thicknesses of hybrid layer consisted of gold and graphene layers are optimized to make our design highly sensitive by using numerical simulations carried out in COMSOL Multiphysics 6. 0 and MATLAB softwares. It yields thicknesses of gold and graphene layers to 40 nm and 9. 52 nm respectively. The proposed design loaded separately with range of analytes of low refractive indices from 1. 30 to 1. 39 exhibiting an outstanding wavelength dependent sensitivity and resolution values of 30, 000 nm/RIU and \ (3. 33 10^-6\) RIU, respectively apart from other promising values of various parameters. These results show that the proposed design possesses a significant improvement in performance over the existing counterparts. The proposed design points out the excellent sensing feature for precise, immediate and reliable detection of disease diagnostics and other biomedical sensing applications.