scholarly journals FDTD Modelling of Silver Nanoparticles Embedded in Phase Separation Interface of H-PDLC

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Kun Gui ◽  
Jihong Zheng ◽  
Kangni Wang ◽  
Daoping Li ◽  
Songlin Zhuang
Keyword(s):  
Silver Nanoparticles ◽  
Phase Separation ◽  
Incident Angle ◽  
Incident Light ◽  
Near Field ◽  
Double Resonance ◽  
Blue Shift ◽  
Resonance Peak ◽  
Localized Surface Plasmon ◽  
Silver Nps

We report localized surface plasmon resonance (LSPR) of silver nanoparticles (NPs) embedded in interface of phase separation of holographic polymer-dispersed liquid crystal (H-PDLC) gratings using Finite-Difference Time Domain method. We show that silver NPs exhibit double resonance peak at the interface, and these peaks are influenced by the angle of incident light. We observe a blue shift of the wavelength of resonance peak as the incident angle increases. However, the location of silver NPs at the interface has nearly no effect on the wavelength of resonance peak. Also we show near-field and far-field properties surrounding silver NPs and find that field distribution can be controlled through rotation of incident angle. Therefore, LSPR properties of silver NPs within H-PDLC gratings can be excited by appropriate wavelength and angle of the incident light.

Optical Analysis of Hole Patterned Ag Nanoparticle Structure

2021 ◽  
Vol 21 (8) ◽  
pp. 4192-4199
Author(s):  
Hyun-Ji Jeon ◽  
Ji-Yeon Kim ◽  
Jinnil Choi
Keyword(s):  
Metal Nanoparticles ◽  
Optical Transmission ◽  
Incident Angle ◽  
Incident Light ◽  
Localized Surface Plasmon ◽  
Optical Analysis ◽  
Optical Noise ◽  
Hole Configuration ◽  
Nanoparticle Structure ◽  
Sub Wavelength

A structure with periodic sub-wavelength nanohole patterns interacts with incident light and causes extraordinary optical transmission (EOT), with metal nanoparticles leading to localized surface plasmon resonance (LSPR) phenomena. To explore the effects of metal nanoparticles (NPs), optical analysis is performed for metal NP layers with periodic hole patterns. Investigation of Ag NP arrangements and comparisons with metal film structures are presented. Ag NP structures with different hole configuration are explored. Also, the effects of increasing light incident angle are investigated for metal NP structures where EOT peak at 460 nm wavelength is observed. Moreover, electric field distributions at each transmittance peak wavelengths and optical noise are analyzed. As a result, optical characteristics of metal NP structures are obtained and differences in resonance at each wavelength are highlighted.

scholarly journals OPTICAL DETERMINATION AND IDENTIFICATION OF ORGANIC SHELLS AROUND NANOPARTICLES: APPLICATION TO SILVER NANOPARTICLES

NANO ◽  
2013 ◽  
Vol 08 (02) ◽  
pp. 1350016 ◽  
Author(s):  
T. MAURER ◽  
N. ABDELLAOUI ◽  
A. GWIAZDA ◽  
P.-M. ADAM ◽  
A. VIAL ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Organic Layer ◽  
Simple Method ◽  
Optical Extinction ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Silver Nps ◽  
Optical Determination

We present a simple method to prove the presence of an organic shell around silver nanoparticles (NPs). This method is based on the comparison between optical extinction measurements of isolated NPs and Mie calculations predicting the expected wavelength of the Localized Surface Plasmon Resonance of the NPs with and without the presence of an organic layer. This method was applied to silver NPs which seemed to be well protected from oxidation. Further experimental characterization via surface enhanced raman spectroscopy (SERS) measurements allowed to identify this protective shell as ethylene glycol. Combining LSPR and SERS measurements could thus give proof of both presence and identification for other plasmonic NPs surrounded by organic shells.

Enhancement of Optical Transmission Through Planar Nano-Apertures in a Metal Film

2003 ◽  
Author(s):  
Eric X. Jin ◽  
Xianfan Xu
Keyword(s):  
Metal Film ◽  
Incident Light ◽  
Near Field ◽  
Transmission Efficiency ◽  
Localized Surface Plasmon ◽  
Fabry Perot ◽  
Wavelength Resolution ◽  
Signal Contrast ◽  
Negative Role ◽  
Sub Wavelength

In this work, we investigate transmission enhancement through ridged-apertures of nanometer size in a metal film in the optical frequency range. It is demonstrated that the fundamental propagation TE10 mode concentrated in the gap between the two ridges of the aperture provides transmission efficiency higher than unity, and the size of the gap between the two ridges determines the sub-wavelength resolution. Fabry-Perot-like resonance with respect to the thickness of the aperture and the red-shift phenomena with respect to the wavelength of the incident light are observed. As a comparison, transmission through regular apertures is also computed, and is found much lower. Localized surface plasmon (LSP) is excited on the edges of the aperture in a silver film but plays a negative role with respect to the field concentration and signal contrast. With optimized geometries, the ridged apertures are capable of achieving sub-wavelength resolution in the near field with transmission efficiency above unity and high contrast.

scholarly journals Design and Optimization of Plasmon Resonance Sensor Based on Micro–Nano Symmetrical Localized Surface

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 841
Author(s):  
Fengyu Yin ◽  
Jin Liu ◽  
Haima Yang ◽  
Aleksey Kudreyko ◽  
Bo Huang
Keyword(s):  
Refractive Index ◽  
Plasmon Resonance ◽  
Incident Angle ◽  
Near Field ◽  
Measurement Techniques ◽  
Fdtd Simulation ◽  
Localized Surface Plasmon ◽  
Small Scale ◽  
Surface Plasma Resonance ◽  
Resonance Sensor

Surface Plasma resonance (SPR) sensors combined with biological receptors are widely used in biosensors. Due to limitations of measurement techniques, small-scale, low accuracy, and sensitivity to the refractive index of solution in traditional SPR prism sensor arise. As a consequence, it is difficult to launch commercial production of SPR sensors. The theory of localized surface plasmon resonance (LSPR) developed based on SPR theory has stronger coupling ability to near-field photons. Based on the LSPR sensing theory, we propose a submicron-sized golden-disk and graphene composite structure. By varying the thickness and diameter of the array disk, the performance of the LSPR sensor can be optimized. A graphene layer sandwiched between the golden-disk and the silver film can prevent the latter from oxidizing. Symmetrical design enables high-low concentration of dual-channel distributed sensing. As the fixed light source, we use a 632.8-nm laser. A golden nano-disk with 45 nm thickness and 70 nm radius is designed, using a finite difference time domain (FDTD) simulation system. When the incident angle is 42°, the figure of merit (FOM) reaches 8826, and the measurable refractive index range reaches 0.2317.

Experimental Study of Enhancement and Quenching of Plasmon-Controlled Fluorescence Using Quantum Dot–Plasmonic Nanoparticle Mixtures in Aqueous Medium

2012 ◽  
Author(s):  
Nola Palombo ◽  
Timothy Walsh ◽  
Jungchul Lee ◽  
Keunhan Park
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Quantum Dot ◽  
Near Field ◽  
Emission Spectra ◽  
Emission Wavelength ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Distilled Water ◽  
Plasmonic Nanoparticle

This article reports the enhancement and quenching of quantum dot (QD) emission for different concentrations of plasmonic nanoparticles (PNPs) by utilizing the Brownian motion-induced dynamic near-field interactions in aqueous solution. We measured the fluorescence spectrum of two types of QD-PNP mixtures. The first mixture was QDs (525 nm for emission wavelength) and gold nanoparticles dispersed in distilled water, where the emission wavelength of the QDs matches the localized surface plasmon (LSP) excitation wavelength of the gold nanoparticles. The second mixture was QDs (655 nm for emission wavelength) and silver nanoparticles dispersed in distilled water, where LSPs excited at the wavelength of 392 nm affect the excitation of the QDs. For both experiments, the QD emission spectra were monitored while changing the concentration of the PNPs from 108 to 1011 /mL for a fixed concentration of QDs at 1 × 1013 /mL. For low PNP concentrations, the QD emission was enhanced for 30 nm gold nanoparticles and 80 nm silver nanoparticles; however, for high PNP concentrations, the QD emission was always quenched. This research reveals the dependence of the QD fluorescence on the concentration of PNPs. The obtained results will be beneficial in further understanding plasmonic interactions between QDs and nanoparticles and the manipulation of QD emission, switching from enhancement to quenching or vice versa, with the alteration of nanoparticle concentration.

scholarly journals Evolution of Electronic State and Properties of Silver Nanoparticles during Their Formation in Aqueous Solution

2021 ◽  
Vol 22 (19) ◽  
pp. 10673
Author(s):  
Vadim Ershov ◽  
Natalia Tarasova ◽  
Boris Ershov
Keyword(s):  
Silver Nanoparticles ◽  
Electronic State ◽  
Electron Density ◽  
Quantitative Relationship ◽  
Blue Shift ◽  
Localized Surface Plasmon ◽  
Free Electrons ◽  
Band Shape ◽  
Transmission Electron ◽  
And Shifts

The electron density of a nanoparticle is a very important characteristic of the properties of a material. This paper describes the formation of silver nanoparticles (NPs) and the variation in the electronic state of an NP’s surface upon the reduction in Ag+ ions with oxalate ions, induced by UV irradiation. The calculations were based on optical spectrophotometry data. The NPs were characterized using Transmission electron microscopy and Dynamic light scattering. As ~10 nm nanoparticles are formed, the localized surface plasmon resonance (LSPR) band increases in intensity, decreases in width, and shifts to the UV region from 402 to 383 nm. The interband transitions (IBT) band (≤250 nm) increases in intensity, with the band shape and position remaining unchanged. The change in the shape and position of the LSPR band of silver nanoparticles in the course of their formation is attributable to an increasing concentration of free electrons in the particles as a result of a reduction in Ag+ ions on the surface and electron injection by CO2− radicals. The ζ-potential of colloids increases with an increase in electron density in silver nuclei. A quantitative relationship between this shift and electron density on the surface was derived on the basis of the Mie–Drude theory. The observed blue shift (19 nm) corresponds to an approximately 10% increase in the concentration of electrons in silver nanoparticles.

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