Design and Analysis of Arc-Shaped Single Core Photonic Crystal Fiber Sensor Based on Surface Plasmon Resonance

The selection of a suitable plasmonic material is extremely crucial for achieving high-performance photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensors. However, most numerical investigations to date are limited to PCF-SPR sensors with conventional circularly coated plasmonic metals due to their availability and rigid properties. In this work, a single-core arc-shaped photonic crystal fiber is designed and studied with sensing ingredients coated outside the fiber. The simulation and numerical analyses were performed using the full-vector finite element method (FV-FEM) to examine the effects of using gold as active metal and also the deposition of $Ta_2 O_5$ on gold. The results show that the arc-shaped sensor with gold film can obtain the maximum wavelength interrogation sensitivity (WIS) of 9500 nm/RIU within the refractive index (RI) range of 1.25 to 1.39 while the maximum amplitude interrogation sensitivity (AIS) is reached 579.26 $RIU^{-1}$ at 1.39 and resolution is found to be 1.05 x ${10^{-5}}$. However, depositing $Ta_2 O_5$ on the gold gives an improved maximum WIS and AIS of 22000 nm/RIU, and 1209.21 $RIU^{-1}$, respectively. With the coating of $Ta_2 O_5$, the resolution improves to 4.55 x ${10^{-6}}$ making the proposed sensor design undoubtedly effective in detecting different biological samples with a wide range of RI.