Electromagnetic Model of a SPR Sensor Coupled to Array of Nanoparticles by Periodic Green’s Function

André Cruz,Tommaso Del Rosso,Victor Dmitriev,Karlo Costa

doi:10.1155/2019/7548243

Abstract

In this paper, we present a theoretical study of a Surface Plasmon Resonance Sensor in the Surface Plasmon Coupled Emission (SPCE) configuration. A periodic planar array of core-shell gold nanoparticles (AuNps), chemically functionalized to aggregate fluorescent molecules, is coupled to the sensor structure. These nanoparticles, characterized as target particles, are modeled as equivalent nanodipoles. The electromagnetic modeling of the device was performed using the spectral representation of the magnetic potential by Periodic Green’s Function (PGF). Parametric results of spatial electric and magnetic fields are presented at wavelength 632.8nm. We also present a spectral analysis of the magnetic potential, where we verify the appearance of the surface plasmon polariton (SPP) waves. To validate the analytical method, we compared the limit case of small concentration of nanoparticles with published works. We also present a convergence analysis of the solution as a function of the concentration of nanoparticles in the periodic array. The results show that the theoretical method of PFG can be efficiently used as a tool for design of this sensing device.

Highlights

In the last two decades, the development of new optical devices based on metallic structures has been of great interest
The interaction between metals and electromagnetic waves, in the optical regime, produces a collective oscillatory behavior in the gas of free electrons in the metal in phase opposite to the incident field, resulting in the formation of a surface wave with evanescent characteristic in the metal/dielectric interface, known as surface plasmon wave [3]. This phenomenon is related to the negative real part of the dielectric function of metal, which occurs when the excitation is due by optical fields [3, 4]. In view of these properties, noble metals have been used for development of devices based on the Surface Plasmon Resonance (SPR), in planar structures, and Localized Surface Plasmon Resonance (LSPR), in isolated metallic nanoparticles [3,4,5]
Research has shown that, on particular conditions, surface plasmon polariton (SPP) waves can be efficiently used to control the near field intensification in metal nanostructures [6, 7]. The study of these phenomena has been of great importance for the development of SPR sensors devices for applications in biosensing, photodetection, spectroscopy, and detection of metallic nanopoluents resulting from nanofabrication processes [7, 8]

Summary

Introduction

In the last two decades, the development of new optical devices based on metallic structures has been of great interest. The interaction between metals and electromagnetic waves, in the optical regime, produces a collective oscillatory behavior in the gas of free electrons in the metal in phase opposite to the incident field, resulting in the formation of a surface wave with evanescent characteristic in the metal/dielectric interface, known as surface plasmon wave [3] This phenomenon is related to the negative real part of the dielectric function of metal, which occurs when the excitation is due by optical fields [3, 4]. Research has shown that, on particular conditions, SPP waves can be efficiently used to control the near field intensification in metal nanostructures [6, 7] The study of these phenomena has been of great importance for the development of SPR sensors devices for applications in biosensing, photodetection, spectroscopy, and detection of metallic nanopoluents resulting from nanofabrication processes [7, 8].

Objectives

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Conclusion