Surface plasmon resonance based highly sensitive gold coated PCF biosensor

Abstract

A highly sensitive surface plasmon resonance-based PCF biosensor is explored in this research work. Outside the fiber frame, active plasmonic material gold (Au) with a thickness of 25 nm has been deposited which is chemically steady and is the primary sensing layer of the presented sensor. Unknown analytes could be detected by being flown on the metal surface or leaked onto the metal layer’s outer surface. In this paper, we used circular airholes for external sensing of the unknown analyte. The suggested sensor obtains the maximum wavelength sensitivity of 14,500 nm / RIU in X-polarization mode and the maximum amplitude sensitivity of 4738.9 $${\mathrm{RIU}}^{-1}$$ for Y-polarized mode, respectively in the spectrum of 1.35–1.41 for the analyte refractive index (RI). The lowest wavelength sensor resolution offered by this sensor is 6.9× $${10}^{-6}$$ RIU and the lowest amplitude sensor resolution is 2.11×10-6 RIU for Y-polarized mode with FOM of 387 and 364 for X and Y polarization. In the presence of a perfectly matched layer (PML), the sensing output of the presented sensor is analyzed using the finite element method (FEM) based software named COMSOL Multiphysics version 5.3a. From our simulation result, it is important to note that the proposed sensor demonstrates a noteworthy sensor performance for both polarization modes so that the choice of light sources during the practical implementation is more frequent. The findings also show some bright features that our proposed sensor can detect organic chemicals, biochemical analytes and can also be used in medical diagnostics immensely.