Design of an ultra-sensitive bimetallic anisotropic PCF SPR biosensor for liquid analytes sensing

In this research work, an anisotropic photonic crystal fiber (PCF) biosensor working on a refractive index (RI) variation and based on surface plasmon resonance (SPR) is presented. Liquid analytes (LA) having a RI within the range of 1.340 to 1.380 RIU are investigated from the proposed biosensor. Spectroscopy analysis of LA having RI values of 1.340 RIU, 1.360 RIU, and 1.380 RIU is performed from the developed sensing setup for modeling an ultrasensitive biosensor. The numerical analysis of the sensing parameters for the proposed sensor presents a maximum wavelength sensitivity (WS) of 20000 nm/RIU for x- polarization (x - pol.) and 18000 nm/RIU for y- polarization (y - pol.), respectively, using the wavelength interrogation technique. Maximum amplitude sensitivity (AS) of 2158 RIU^-1 and 3167 RIU^-1 is obtained for x -  pol. and y -  pol., respectively, using the amplitude interrogation technique. Maximum sensor resolution (SR) of 5.00 × 10^-6RIU and 5.55 × 10^-6RIU is obtained for x -  pol. and y -  pol., respectively. The linear relationship of the resonant wavelength (RW) with the RI produces R² =   0.9972 and R² = 0.9978, corresponding to a degree (2) for x -  pol. and y -  pol., respectively. The figure of merit (FOM) for x - pol. and y -  pol. are 93.45 RIU^-1 and 105.88 RIU^-1, respectively. The sensing parameters have obtained the maximum value for the LA having a RI value of 1.375 RIU.