Ultrahigh sensitivity refractive index biosensor based on gold coated nano-film photonic crystal fiber

Abstract

A high sensitivity gold coated circular nano-film photonic crystal fiber (PCF) biosensor based on surface plasmon resonance (SPR) is proposed. Finite element method (FEM) has been applied to simulate and analyze the sensing performance of the proposed circular structure. The highest sensitivity response and birefringence of 45003.05 nm/RIU and 1.9 × 102 are obtained respectively, where the operating refractive index (RI) analyte range is 1.33–1.40 and the gold layer thickness is 50 nm. It is the maximum sensitivity response where the RI analyte range is 1.33–1.40. Changing the gold layer thickness, the sensitivity response of 48269.50 nm/RIU is achieved for 70 nm gold layer where the operating gold layer thickness range is 40 nm to 90 nm. In short, the suggested circular SPR PCF structure can be broadly applicable in RI sensing applications for its outstanding sensitivity response, simple compact structure design and tunable performance.