Determination of the Bimetallic Layers’ Film Thicknesses by Phase Detection of SPR Prism Coupler

Liu, Chao; Liu, Qinggang; Qin, Zirui; Xie, Xian Ning

doi:10.1007/s11468-016-0376-1

Cited by 11 publications

(4 citation statements)

References 25 publications

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“…Because phase sensitivity configuration is less sensitive to external impacts, it may be utilized to improve the sensitivity of SPR biosensors [ 13 , 14 , 15 ]. The fact that the phase of the incident light wave’s transverse magnetic (TM) polarized component varies significantly while the phase of the transverse electric (TE) stays mostly constant serves as the foundation for this configuration [ 16 , 17 ]. Silver (Ag) is favored as an active metal for SPR sensors due to its lower D-electron energy bands and bulk plasma frequency [ 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

An Improved Seeker Optimization Algorithm for Phase Sensitivity Enhancement of a Franckeite- and WS2-Based SPR Biosensor for Waterborne Bacteria Detection

Yue,

Zhao,

Tao

et al. 2024

Micromachines

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For the purpose of detecting waterborne bacteria, a high-phase-sensitivity SPR sensor with an Ag–TiO2–Franckeite–WS2 hybrid structure is designed using an improved seeker optimization algorithm (ISOA). By optimizing each layer of sensor construction simultaneously, the ISOA guarantees a minimum reflectance of less than 0.01 by Ag (20.36 nm)–TiO2 (6.08 nm)–Franckeite (monolayer)–WS2 (bilayer) after 30 iterations for E. coli. And the optimal phase sensitivity is 2.378 × 106 deg/RIU. Sensor performance and computing efficiency have been greatly enhanced using the ISOA in comparison to the traditional layer-by-layer technique and the SOA method. This will enable sensors to detect a wider range of bacteria with more efficacy. As a result, the ISOA-based design idea could provide SPR biosensors with new applications in environmental monitoring.

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Section: Introductionmentioning

confidence: 99%

An Improved Seeker Optimization Algorithm for Phase Sensitivity Enhancement of a Franckeite- and WS2-Based SPR Biosensor for Waterborne Bacteria Detection

Yue,

Zhao,

Tao

et al. 2024

Micromachines

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“…The surface plasmon resonance (SPR)-based sensing method provides the real-time and label-free capability for measuring biomolecular interactions . The most common method employs an optical prism to excite SPR on the metal surface, and changes in surface refractive index are subsequently detected which helps quantify surface binding biomolecules. − Aside from the prism-based SPR, previous research also indicates that SPR could be directly excited by using metallic nanostructures. − For example, nanohole array and periodic nanoslit with the Fano resonances have been proposed and applied to various kinds of biomolecular detections. − The Fano resonance is an asymmetrical and sharp resonant profile in optical spectra induced by multiple optical resonant mode coupling of heterogeneous nanomaterials or nanostructures. − Compared to the conventional prism-based SPR, the nanostructure-based plasmonic excitation method possesses chip-based features, high access in detection, and high-throughput capabilities. − Furthermore, based on the peak shift or intensity change analysis of the Fano resonance, it pushes the boundaries of sensitivity. These characteristics thus attract great attention and address various sensing areas, such as protein interactions, food safety, and environment monitoring. − …”

Section: Introductionmentioning

confidence: 99%

Sensitive Oligonucleotide Detection Using Resonant Coupling between Fano Resonance and Image Dipoles of Gold Nanoparticles

Kuo

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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The surface plasmon resonance (SPR)-based sensor has been widely used for biodetection. One of the attractive roles is the gold nanostructure with Fano resonance. Its sharp resonant profile takes advantage of the high figure of merit (FoM) in high-sensitivity detection. However, it is still difficult to detect small molecules at low concentrations due to the extremely low refractive index changes on the metallic surface. We propose using the coupling of image dipoles of gold nanoparticles (AuNPs) and Fano resonance of periodic capped gold nanoslits (CGNs) for sensitive small-molecule detections. The coupling mechanism was verified by three-dimensional finite-difference timedomain calculations and experiments. AuNPs on CGN form image dimer assemblies and induce image dipole with resonance wavelengths ranging from 730 to 550 nm. The surface plasmon polaritons (SPPs) interact with the image dipole of the AuNP on the CGNs and then scatter out through the periodic gold caps. The experimental results show that the peak intensity of grating resonance is decreased by the effect of image dipole and exhibits the maximum intensity change when the Fano resonance matches the resonance of image dipole. The 50 nm AuNPs can be detected with a surface density of less than one particle/μm 2 by using the intensity change as the signal. With the resonant coupling between Fano resonance and image dipole extinction, the oligonucleotide with a molecular weight of 5.5 kDa can be detected at a concentration of 100 fM. The resonant coupling dramatically pushes the sensitivity boundary, and we report the limit of detection (LOD) to be 3 orders of magnitude lower than that of the prism-based SPR. This study provides a promising and efficient method for detecting low concentrations of small molecules such as aptamers, miRNA, mRNA, and peptides.

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“…In both cases, the SPs are excited in the metal film by the ATR mechanism, and the field of SPs decays exponentially on both sides of the boundary. Thus, the SPR is extremely sensitive to changes in the refractive index of the surrounding medium (analyte), and is accompanied by a drop in the reflected intensity [4,5,10,11], or by an abrupt phase change [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…Optical phase detection techniques [21][22][23] provide a large number of approaches, including heterodyne interferometry [24,25], interferometry with a Mach-Zehnder [12,[26][27][28] or imaging interferometer [13], phase quadrature interferometry [29], a phase-shifted polarimetric scheme [30], schemes with a photo-elastic [14] or electro-optic [15] modulator, and a rotating analyzer method [17]. Recently, techniques of spectral interferometry [18][19][20]31,32] and holographic microscopy [33] have emerged as effective tools too.…”

Section: Introductionmentioning

confidence: 99%

Surface Plasmon Resonance-Based Sensing Utilizing Spatial Phase Modulation in an Imaging Interferometer

Kaňok

Ciprián

Hlubina

2020

Sensors

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Spatial phase modulation in an imaging interferometer is utilized in surface plasmon resonance (SPR) based sensing of liquid analytes. In the interferometer, a collimated light beam from a laser diode irradiating at 637.1 nm is passing through a polarizer and is reflected from a plasmonic structure of SF10/Cr/Au attached to a prism in the Kretschmann configuration. The beam passes through a combination of a Wollaston prism, a polarizer and a lens, and forms an interference pattern on a CCD sensor of a color camera. Interference patterns obtained for different liquid analytes are acquired and transferred to the computer for data processing. The sensing concept is based on the detection of a refractive index change, which is transformed via the SPR phenomenon into an interference fringe phase shift. By calculating the phase shift for the plasmonic structure of SF10/Cr/Au of known parameters we demonstrate that this technique can detect different weight concentrations of ethanol diluted in water, or equivalently, different changes in the refractive index. The sensitivity to the refractive index and the detection limit obtained are −278 rad/refractive-index-unit (RIU) and 3.6 × 10 − 6 RIU, respectively. The technique is demonstrated in experiments with the same liquid analytes as in the theory. Applying an original approach in retrieving the fringe phase shift, we revealed good agreement between experiment and theory, and the measured sensitivity to the refractive index and the detection limit reached −226 rad/RIU and 4.4 × 10 − 6 RIU, respectively. These results suggest that the SPR interferometer with the detection of a fringe phase shift is particularly useful in applications that require measuring refractive index changes with high sensitivity.

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Determination of the Bimetallic Layers’ Film Thicknesses by Phase Detection of SPR Prism Coupler

Cited by 11 publications

References 25 publications

An Improved Seeker Optimization Algorithm for Phase Sensitivity Enhancement of a Franckeite- and WS2-Based SPR Biosensor for Waterborne Bacteria Detection

An Improved Seeker Optimization Algorithm for Phase Sensitivity Enhancement of a Franckeite- and WS2-Based SPR Biosensor for Waterborne Bacteria Detection

Sensitive Oligonucleotide Detection Using Resonant Coupling between Fano Resonance and Image Dipoles of Gold Nanoparticles

Surface Plasmon Resonance-Based Sensing Utilizing Spatial Phase Modulation in an Imaging Interferometer

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