Highly sensitive tetra-slotted gold-coated spiral plasmonic biosensor with a large detection range

An extremely highly sensitive photonic crystal fiber (PCF) based SPR or surface plasmon resonance biosensor is manifested in this article, in a cumulated form of circularly slotted spiral lattice structure (SLS). The numerical performance analysis of the sensor is critically interpreted using the finite element method (FEM), including a perfectly matched layer (PML) and scattering boundary conditions. Very well known chemically stable material gold is used as the plasmonic material and implanted inside the circular slots to lessen the fabrication challenge and oxidation problem. The prospective model shows the maximum value of sensitivity is 41,000 nm/RIU, employing the method of wavelength interrogation and a maximum value of sensitivity of 4242 RIU−1, using the method of amplitude interrogation. The proposed sensor has the capability of detecting analytes in a massive range of the refractive index 1.32 to 1.50 RIU (for wavelength 0.5 µm to 1.55 µm) with a highest sensor resolution of 2.44 × 10−6 RIU. It is highly capable of identifying biomolecules like benzene, carbon tetrachloride, ethyl alcohol, acetone, water, silicon oil, and glucose solution in water, fused silica, cornea, lens, liver cell, and intestinal mucosa of human, polylactic acid, vegetable oil, and glycerol, etc. The sensor exhibits high linearity by showing R2 value 0.97 with a maximum FOM of 683 RIU−1. For large detection range, immense sensitivity, high FOM, and low fabrication complexity, the illustrated sensor can be a supreme candidate in the realm of SPR biosensor.