A Highly Sensitive Gold-Coated Photonic Crystal Fiber Biosensor Based on Surface Plasmon Resonance

Md Hasan,Sanjida Akter,Sohel Rana,Sharafat Ali,Ahmmed Rifat

doi:10.3390/photonics4010018

Abstract

In this paper, we numerically demonstrate a two-layer circular lattice photonic crystal fiber (PCF) biosensor based on the principle of surface plasmon resonance (SPR). The finite element method (FEM) with circular perfectly matched layer (PML) boundary condition is applied to evaluate the performance of the proposed sensor. A thin gold layer is deposited outside the PCF structure, which acts as the plasmonic material for this design. The sensing layer (analyte) is implemented in the outermost layer, which permits easy and more practical fabrication process compared to analyte is put inside the air holes. It is demonstrated that, at gold layer thickness of 40 nm, the proposed sensor shows maximum sensitivity of 2200 nm/RIU using the wavelength interrogation method in the sensing range between 1.33–1.36. Besides, using an amplitude interrogation method, a maximum sensitivity of 266 RIU−1 and a maximum sensor resolution of 3.75 × 10−5 RIU are obtained. We also discuss how phase matching points are varied with different fiber parameters. Owing to high sensitivity and simple design, the proposed sensor may find important applications in biochemical and biological analyte detection.

Highlights

In recent years, surface plasmon resonance (SPR) phenomenon has become a hot topic because of its widespread applications in multidisciplinary fields
The fundamental operating mechanism of photonic crystal fiber (PCF)-based SPR sensors depends on the mutual interaction between evanescent field and surface electrons, which occurs in the metal–dielectric interface
The numerical investigations were performed by using finite element method (FEM) with perfectly matched layer (PML) and scattering boundary conditions

Summary

Introduction

Surface plasmon resonance (SPR) phenomenon has become a hot topic because of its widespread applications in multidisciplinary fields. The fundamental working principle of a prism coupling SPR sensor is based on the interaction of plasmonic materials and incident transverse magnetic (TM) or p-polarized light. The incident light (photons) has a certain frequency; when this frequency resembles that of the surface electrons of the plasmonic material, the p-polarized light stimulates the free electrons of the metal surface. Due to these collective oscillations, a surface plasmon wave (SPW) is originated in the metal–dielectric interface

Methods

Results

Conclusion