Analysis of Effects of Surface Roughness on Sensing Performance of Surface Plasmon Resonance Detection for Refractive Index Sensing Application.

Treesukon Treebupachatsakul,Suejit Pechprasarn,Siratchakrit Shinnakerdchoke

doi:10.3390/s21186164

Abstract

This paper provides a theoretical framework to analyze and quantify roughness effects on sensing performance parameters of surface plasmon resonance measurements. Rigorous coupled-wave analysis and the Monte Carlo method were applied to compute plasmonic reflectance spectra for different surface roughness profiles. The rough surfaces were generated using the low pass frequency filtering method. Different coating and surface treatments and their reported root-mean-square roughness in the literature were extracted and investigated in this study to calculate the refractive index sensing performance parameters, including sensitivity, full width at half maximum, plasmonic dip intensity, plasmonic dip position, and figure of merit. Here, we propose a figure-of-merit equation considering optical intensity contrast and signal-to-noise ratio. The proposed figure-of-merit equation could predict a similar refractive index sensing performance compared to experimental results reported in the literature. The surface roughness height strongly affected all the performance parameters, resulting in a degraded figure of merit for surface plasmon resonance measurement.

Highlights

Surface plasmons are oscillations due to moving electrons that exist at an interface between conductors and dielectrics [1]
We proposed a theoretical analysis quantifying the effect of plasmonic gold sensor roughness on its refractive index sensing capability using rigorous coupledwave analysis
surface plasmon resonance (SPR) sensor surface profiles with different roughness heights and roughness periods were modeled using a digital random number generator and a low-pass filter to limit the spatial frequency of the roughness to mimic the surface morphology reported in the literature

Summary

Introduction

Surface plasmons are oscillations due to moving electrons that exist at an interface between conductors and dielectrics [1]. This phenomenon can generate a resonating effect when illuminated by an external electric field called surface plasmon resonance (SPR) [2]. The surface plasmon polariton (SPP)-based sensor can be classified into two primary configurations: Otto [14] and Kretschmann [15] configurations, as shown in Figure 1a,b [6]. A beam of p-polarized coherent incident light penetrates through a glass prism, illuminates the thin noble metal surface, and reflects off the metal surface

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