Spatial evolution of the near-field distribution on planar gold nanoparticles with the excitation wavelength across dipole and quadrupole modes

2017 ◽  
Vol 5 (3) ◽  
pp. 187 ◽  
Author(s):  
Jinghuan Yang ◽  
Quan Sun ◽  
Han Yu ◽  
Kosei Ueno ◽  
Hiroaki Misawa ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Field Distribution ◽  
Near Field ◽  
Excitation Wavelength ◽  
Spatial Evolution

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 Enhancement in Inverse Pyramid SERS Substrates with Entrapped Gold Nanoparticles

2019 ◽  
Author(s):  
István Rigó ◽  
Miklos Veres ◽  
László Himics ◽  
Zsuzsanna Pápa ◽  
Orsolya Hakkel ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electromagnetic Field ◽  
Gold Nanoparticle ◽  
Field Distribution ◽  
Time Domain ◽  
Near Field ◽  
Field Enhancement ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Giant plasmonic surface enhancement has been observed in gold coated micron sized inverse pyramids entrapping a gold nanoparticle. The amplification of both surface enhanced Raman and photoluminescence signals was found to be dependent on the diameter of trapped gold nanoparticle and around 50-fold enhancement was detected for 250nm diameter sample relatively to the 50nm one. Finite differential time domain simulations, performed to determine the near-field distribution in the structure, showed that when the nanoparticle protrudes into the hotspot zone of the void, coupling of electromagnetic field occurs and the plasmon-related near-field enhancement is concentrated into the close vicinity of the nanoparticle, mainly into the close gaps around the tangential points of the curved sphere and the flat pyramid surface. This results in a more than 15 times increase of the near-field intensity, compared to the empty void.

Near field distribution in two dimensionally arrayed gold nanoparticles on platinum substrate

2007 ◽  
Vol 90 (12) ◽  
pp. 123106 ◽  
Author(s):  
Nikolay Nedyalkov ◽  
Tetsuo Sakai ◽  
Tomoya Miyanishi ◽  
Minoru Obara
Keyword(s):  
Gold Nanoparticles ◽  
Field Distribution ◽  
Near Field

scholarly journals Visualization of microwave near-field distribution in sodium chloride and glucose aqueous solutions by a thermo-elastic optical indicator microscope

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhirayr Baghdasaryan ◽  
Arsen Babajanyan ◽  
Levon Odabashyan ◽  
Jung-Ha Lee ◽  
Barry Friedman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Field Distribution ◽  
Near Field ◽  
Absorption Properties ◽  
Novel Approach ◽  
Concentration Changes ◽  
Biological Liquids ◽  
Optical Indicator ◽  
Distribution Intensity

AbstractIn this study, a new optical method is presented to determine the concentrations of NaCl and glucose aqueous solutions by using a thermo-elastic optical indicator microscope. By measuring the microwave near-field distribution intensity, concentration changes of NaCl and glucose aqueous solutions were detected in the 0–100 mg/ml range, when exposed to microwave irradiation at 12 GHz frequency. Microwave near-field distribution intensity decreased as the NaCl or glucose concentration increased due to the changes of the absorption properties of aqueous solution. This method provides a novel approach for monitoring NaCl and glucose in biological liquids by using a CCD sensor capable of visualizing NaCl and glucose concentrations without scanning.

EXCITON–PLASMON INTERACTION IN MONOLAYERS OF METAL-SEMICONDUCTOR NANOSTRUCTURES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 623-627 ◽  
Author(s):  
M. HARIDAS ◽  
L. N. TRIPATHI ◽  
J. K. BASU
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Blue Shift ◽  
Optical Microscope ◽  
Peak Position ◽  
Photoluminescence Spectra ◽  
Langmuir Blodgett ◽  
Near Field Scanning ◽  
Cdse Nanorods

Effect of shape and density on the energy transfer between metallic nanoparticles and semi conducting nanostructures was studied by observing the photoluminescence spectra using near field scanning optical microscope. The monolayers of gold nanoparticles, CdSe nanorods and composite with different number ratios were prepared using Langmuir Blodgett method. The spectra collected from the films with different number ratios of CdSe and gold shows a systematic variation of peak position and intensity as a function of number density of CdSe . The photoluminescence spectra collected from composite monolayer is blue shifted compared to the spectra from CdSe nanorods monolayer. Further we observed a blue shift in peak position and reduction emission intensity with respect to increase in the fraction of gold nanoparticles and surface density. We have provided explanation for the observed behavior in terms of strong exciton–plasmon interactions in the compact hybrid monolayers.

scholarly journals Reconstruction of the near-field distribution in an X-ray waveguide array

2017 ◽  
Vol 50 (3) ◽  
pp. 701-711 ◽  
Author(s):  
Qi Zhong ◽  
Lars Melchior ◽  
Jichang Peng ◽  
Qiushi Huang ◽  
Zhanshan Wang ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Field Distribution ◽  
Phase Retrieval ◽  
Near Field ◽  
Field Pattern ◽  
Waveguide Array ◽  
X Ray ◽  
Field Patterns ◽  
Thickness Variations ◽  
Far Field Pattern

Iterative phase retrieval has been used to reconstruct the near-field distribution behind tailored X-ray waveguide arrays, by inversion of the measured far-field pattern recorded under fully coherent conditions. It is thereby shown that multi-waveguide interference can be exploited to control the near-field distribution behind the waveguide exit. This can, for example, serve to create a secondary quasi-focal spot outside the waveguide structure. For this proof of concept, an array of seven planar Ni/C waveguides are used, with precisely varied guiding layer thickness and cladding layer thickness, as fabricated by high-precision magnetron sputtering systems. The controlled thickness variations in the range of 0.2 nm results in a desired phase shift of the different waveguide beams. Two kinds of samples, a one-dimensional waveguide array and periodic waveguide multilayers, were fabricated, each consisting of seven C layers as guiding layers and eight Ni layers as cladding layers. These are shown to yield distinctly different near-field patterns.

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