Dual Side Polished PCF Based Surface Plasmonic Refractive Index Sensor for Detection of Water Pollution

Abstract

In this work, a photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor has been designed for water pollution detection. Using the finite element method (FEM), the performance of a dual-side polished PCF has been investigated and reported. The plasmonic material for this design is a thin silver (Ag) layer deposited outside the PCF framework. In addition, a thin layer of Titanium Oxide (TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) was added to protect the silver layer from oxidation. Utilizing the wavelength interrogation method in the sensing range of RI 1.31-1.35, the proposed sensor shows a maximum sensitivity of 3000 nm/RIU at a silver layer thickness of 40 nm. A sensitivity of 2250 nm/RIU was obtained, particularly in the specific value of RI-1.33. Furthermore, a maximum sensitivity of 475 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and a maximum sensor resolution of 5.83×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> RIU were obtained utilizing the amplitude interrogation method. Since the sensor has a sensing range of 1.31 to 1.35 with high sensitivity, it would be a great option for biosensing, organic chemical sensing, and other analytes detection in that range.