Performance Analysis of Ag-TiO\(_2\)-Coated Hexagonal-Shaped Photonic Crystal Fiber Plasmonic Sensor and Ethanol’s Low Water Content Detection

This paper proposed a photonic crystal fiber (PCF) sensor to detect low water content in ethanol. An Ag-TiO \(_2\) ${}_2$ layer is used to achieve high sensitivity of this surface plasmon resonance (SPR)-based sensor. Moreover, TiO \(_2\) ${}_2$ layer reduces chemical instability of silver and enhances SPR effect. This paper carried out numerical analysis of sensor using finite element method (FEM). For evaluating effectiveness of a sensor to detect a target analyte, its confinement loss, sensitivity to changes in amplitude and wavelength can be measured by tuning some impactful parameters like airhole diameter, thickness of silver (Ag) and titanium dioxide (TiO \(_2\) ${}_2$ ). The maximum amplitude sensitivity for detecting ethanol is 963 \(RIU^{-1}\) $RI{U}^{-1}$ and maximum spectral sensitivity is 12,000 nm/RIU. The sensor can detect 100% pure ethanol with respect to pure water. The linearity of the sensors has also been evaluated between refractive index 1.32–1.36, and the regression coefficient ( \(R^2\) $R^2$ ) for this sensor is 0.99961. The fabrication process of the proposed sensor has been discussed elaborately. This under consideration biosensor shows promising feature for organic and biological compound detection due to its stability and excellent sensitivity.