Surface Plasmon, Surface Wave, and Enhanced Evanescent Wave Microscopy

2018

Self Cite

Surface plasmon Resonance (SPR) has recently been of interest for label-free voltage sensing. Several SPR structures have been proposed. However, making a quantitative cross-platform comparison for these structures is not straightforward due to (1) different SPR measurement mechanisms; (2) different electrolytic solution and concentration in the measurement; and (3) different levels of external applied potential. Here, we propose a quantitative approach to make a direct quantitative comparison across different SPR structures, different electrolytic solutions and different SPR measurement mechanisms. There are two structures employed as example in this theoretical study including uniform plasmonic gold sensor and bimetallic layered structure consisting of uniform silver layer (Ag) coated by uniform gold layer (Ag). The cross-platform comparison was carried by several performance parameters including sensitivity (S), full width half maximum (FWHM) and figure of merit (FoM). We also discuss how the SPR measurement mechanisms enhance the performance parameters and how the bimetallic layer can be employed to enhance the FoM by a factor of 1.34 to 25 depending on the SPR detection mechanism.

Section: Resultsmentioning

confidence: 99%

“…The d TF for gold is 0.5 Å [ 28 ]. These two layers, namely Debye layer and Thomas-Fermi layer can then form a double layer capacitor, whose capacitance can be calculated as [ 23 ]:

where

is the capacitance in F of the double layer capacitor. The rest of the variables are the same as described in Equation (1).…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantitative Cross-Platform Performance Comparison between Different Detection Mechanisms in Surface Plasmon Sensors for Voltage Sensing

Suvarnaphaet

2018

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“…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 theory of SPR has been utilized for numerous sensing technology and applications, including host-pathogen detection [3,4], protein interactions [5,6], ultrasonic detections [7], refractive index sensing [8,9], voltage sensing [10], and microscopic imaging application [11,12].…”

Section: Introductionmentioning

confidence: 99%

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

Treebupachatsakul

Shinnakerdchoke

2021

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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.

“…Surface plasmon resonance (SPR) is a guided electromagnetic wave effect on a noble metal surface, in which light is coupled to a surface wave mode through light-matter interaction [1]. The SPR has been utilized in a broad range of biomedical applications, for example, protein kinetics binding [2][3][4], immunoassay [5,6], refractive index sensing [7,8], and voltage sensing [9,10], and ultrasonic sensing [11].…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Non-Interferometry Based Surface Plasmon Resonance Microscopes

Tontarawongsa

Visitsattapongse

2021

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Surface plasmon microscopy has been of interest to the science and engineering community and has been utilized in broad aspects of applications and studies, including biochemical sensing and biomolecular binding kinetics. The benefits of surface plasmon microscopy include label-free detection, high sensitivity, and quantitative measurements. Here, a theoretical framework to analyze and compare several non-interferometric surface plasmon microscopes is proposed. The scope of the study is to (1) identify the strengths and weaknesses in each surface plasmon microscopes reported in the literature; (2) quantify their performance in terms of spatial imaging resolution, imaging contrast, sensitivity, and measurement accuracy for quantitative and non-quantitative imaging modes of the microscopes. Six types of non-interferometric microscopes were included in this study: annulus aperture scanning, half annulus aperture scanning, single-point scanning, double-point scanning, single-point scanning, at 45 degrees azimuthal angle, and double-point scanning at 45 degrees azimuthal angle. For non-quantitative imaging, there is a substantial tradeoff between the image contrast and the spatial resolution. For the quantitative imaging, the half annulus aperture provided the highest sensitivity of 127.058 rad/μm2 RIU−1, followed by the full annulus aperture of 126.318 rad/μm2 RIU−1. There is a clear tradeoff between spatial resolution and sensitivity. The annulus aperture and half annulus aperture had an optimal resolution, sensitivity, and crosstalk compared to the other non-interferometric surface plasmon resonance microscopes. The resolution depends strongly on the propagation length of the surface plasmons rather than the numerical aperture of the objective lens. For imaging and sensing purposes, the recommended microfluidic channel size and protein stamping size for surface plasmon resonance experiments is at least 25 μm for accurate plasmonic measurements.