Gold-ZnO Coated Surface Plasmon Resonance Refractive Index Sensor Based on Photonic Crystal Fiber with Tetra Core in Hexagonal Lattice of Elliptical Air Holes

A photonic crystal fiber ( $$PCF$$ )-based surface plasmon resonance ( $$SPR$$ ) refractive index ( $$RI$$ ) sensor is proposed and presented in this research work. The proposed $$RI$$ sensor can detect chemicals, analytes, and oil samples falling in the $$RI$$ range of $$1.40 \,RIU$$ to $$1.48 \,RIU.$$ The detection capability of the sensor is investigated employing traditional sensor parameters like “wavelength sensitivity,” “amplitude sensitivity (AS),” “sensor resolution,” and “linear relationship between $$RI$$ and resonant wavelength.” A combination of noble material Gold ( $$Au$$ ) and Zinc oxide ( $$ZnO$$ ) is coated as the plasmonic material for electron excitation in the presented sensor design. The sensing parameters obtained from the proposed sensor predict it as a suitable sensor for analytes, household oil, and chemical detection falling in the $$RI$$ range $$1.40 \,RIU$$ to $$1.48 \,RIU.$$