Design and analysis of a gold-coated dual-core photonic crystal fiber bio-sensor using surface plasmon resonance

Abstract

In this work, a simple gold-glazed dual-core photonic crystal fiber (PCF) is inspected by using surface plasmon resonance for biochemical sensing. Based on high sensing performance and chemical substantiality, gold (Au) is selected as plasmonic material to coat the external surface of the design. The target analyte and gold layer are placed on the outer surface of the PCF to offer fabrication simplicity. A central elliptical air hole is embellished to increase structural asymmetry between both cores hence the sensor came out with improved sensing performances. The numerical analysis of the proposed design is investigated employing the finite element method (FEM). The maximum optimized value of wavelength sensitivity is recorded at about 8000 nm/RIU with a resolution of 12.5×10−6 and amplitude sensitivity is achieved 1443 RIU−1 for the refractive index of 1.39. Furthermore, a detailed study is also performed to investigate the effects of varying sensor's geometrical parameters such as the thickness of gold and analyte layer, pitch distance, diameters of cladding air holes, geometrical shapes of air hole at core. According to these results along with simple structural design, the proposed model can be practical enough for biochemical and bio-molecular substance detection.