Surface plasmon resonance biosensor based on gold-coated side-polished hexagonal structure photonic crystal fiber.

Tiesheng Wu,Maoxiang Hou,Changrui Liao,Shaoqing Cao,Jun He,Ying Wang,Yijian Huang,Feng Zhang,Weiping Cao,Yu Shao,Yiping Wang

doi:10.1364/oe.25.020313

Abstract

The refractive index sensing characteristics of the side-polished photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor are detailed investigated in this paper. We used the finite element method (FEM) to study the influences of the side-polished depth, air hole size, lattice constant, and the refractive index (RI) of the PCF material on sensing performance. The simulation results show that the side-polished depth, air hole size, lattice pitch have significant influence on the coupling strength between core mode and surface plasmon polaritons (SPPs), but have little influence on sensitivity; the coupling strength and sensitivity will significant increase with the decrease of RI of the PCF material. The sensitivity of the D-shaped PCF sensor is obtained to be as high as 21700 nm/RIU in the refractive index environment of 1.33-1.34, when the RI of the PCF material is controlled at 1.36. It revealed a new method of making ultra-high sensitivity SPR fiber sensor. Then we experimental demonstrated a SPR refractive sensor based on the side-polished single mode PCF and investigated the sensing performance. The experimental results of the plasmon resonance wavelength sensitivity agree well with the theoretical results. The presented gold-coated D-shaped PCF SPR sensor could be used as a simple, cost-effective, high sensitivity device in bio-chemical detection.

Highlights

Surface plasmon resonance technology can serve as a basis of many standard tools used to measure the extent that electromagnetic wave can be absorbed into the metal-dielectric structure
It is noteworthy that Xie et al [19,20] experimental researched the influences of side-polished depths and sensing layer thicknesses on D-shaped photonic crystal fiber surface plasmon resonance sensors, and concluded that the sensitivity increases as the sensing layer thickness increases
The theoretical value of the wavelength sensitivity (21700 nm/RIU) is highest sensitivity reported in D-shaped fiber surface plasmon resonance (SPR) senor [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,25,26]. Compared to these design strategies of by the introduction of a small hollow core into microstructured optical fiber (MOF) [1,11], optimizing air holes arrayed in MOF cladding [4,5,6,7,8,9,10], and sensitization processing at the polished surface [27], making photonic crystal fiber (PCF) with lower refractive index (RI) material is a more effective method for improving sensitivity in D-shaped fiber SPR sensor

Summary

Introduction

Surface plasmon resonance technology can serve as a basis of many standard tools used to measure the extent that electromagnetic wave can be absorbed into the metal-dielectric structure (typically gold or silver with dielectric). It is noteworthy that Xie et al [19,20] experimental researched the influences of side-polished depths and sensing layer thicknesses on D-shaped photonic crystal fiber surface plasmon resonance sensors, and concluded that the sensitivity increases as the sensing layer thickness increases. It decreases slightly when the side-polished depth is going up with a certain range. Compared to reports in [19,20], our experimental results are closer to theoretical values with improved sensing performance

Theoretical analysis

Conclusion