53 results match your criteria interparticle interference

Multilayer Diffraction Reveals That Colloidal Superlattices Approach the Structural Perfection of Single Crystals.

ACS Nano 2021 Jan 22. Epub 2021 Jan 22.

Nanochemistry Department, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.

Colloidal superlattices are fascinating materials made of ordered nanocrystals, yet they are rarely called "atomically precise". That is unsurprising, given how challenging it is to quantify the degree of structural order in these materials. However, once that order crosses a certain threshold, the constructive interference of X-rays diffracted by the nanocrystals dominates the diffraction pattern, offering a wealth of structural information. Read More

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January 2021

Biogenic Ag Nanoparticles from Neem Extract: Their Structural Evaluation and Antimicrobial Effects against and (NII 08123).

ACS Biomater Sci Eng 2020 01 11;6(1):235-245. Epub 2019 Dec 11.

Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.

Silver nanocrystals have been successfully fabricated by the bioreduction route using the ethanolic extract of (neem) leaves as the reducing and capping agent without solvent interference. The silver nanocrystals were grown in a single-step method, without the influence of external energy or surfactants, and at room temperature. The nanoparticles were prepared from different ratios of silver ions to reducing agent molecules and were characterized by UV-vis spectroscopy and transmission electron microscopy (TEM). Read More

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January 2020

Surface-enhanced Raman spectroscopy integrated with aligner mediated cleavage strategy for ultrasensitive and selective detection of methamphetamine.

Anal Chim Acta 2021 Feb 21;1146:124-130. Epub 2020 Dec 21.

Research Center for Analytical Instrumentation, Institute of Cyber-Systems and Control, State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027, PR China; Department of Chemistry, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, PR China. Electronic address:

New drugs and illicit synthesized mixtures detection at crime scenes is a great challenge for detection method, which requires anti-interference and ultrasensitive methods to detect methamphetamine (METH) in seized street samples and biological fluids. Herein, we constructed a surface-enhanced Raman sensing method based on aligner mediated cleavage (AMC) of nucleic acid for quantitative detection of METH for the first time. This method we proposed relied on AMC to achieve programmable sequence-specific cleavage of METH aptamer linked by gold nanoparticles (METH aptamer-Au NPs), the cleavage product-Au NPs conjugates (cleavage aptamer-Au NPs) would hybridize with complementary DNA (cDNA)-Au NPs, resulting in the aggregation of the Au NPs and concomitant plasmonic coupling effect. Read More

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February 2021

Bright Field Structural Colors in Silicon-on-Insulator Nanostructures.

ACS Appl Mater Interfaces 2021 Jan 3;13(3):4364-4373. Epub 2021 Jan 3.

Key Laboratory of Microelectronic Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, No.3 West Road, Beitucheng, Beijing 100029, China.

Structural coloration with artificially nanostructured materials is emerging as a prospective alternative to traditional pigments for the high resolution, sustainable recycling, and long-time durability. However, achieving bright field structural colors with dielectric nanostructures remains a great challenge due to the weak scattering in an asymmetric environment. Here, we demonstrate all-dielectric bright field structural colors with diffraction-limited resolution on the silicon-on-insulator platform. Read More

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January 2021

Nanoparticle meta-grid for enhanced light extraction from light-emitting devices.

Light Sci Appl 2020 16;9:122. Epub 2020 Jul 16.

Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City, London, W12 0BZ UK.

Based on a developed theory, we show that introducing a meta-grid of sub-wavelength-sized plasmonic nanoparticles (NPs) into existing semiconductor light-emitting-devices (LEDs) can lead to enhanced transmission of light across the LED-chip/encapsulant interface. This results from destructive interference between light reflected from the chip/encapsulant interface and light reflected by the NP meta-grid, which conspicuously increase the efficiency of light extraction from LEDs. The "meta-grid", should be inserted on top of a conventional LED chip within its usual encapsulating packaging. Read More

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Mediation of resonance energy transfer by two polarisable particles.

A Salam

J Chem Phys 2019 Dec;151(24):244119

Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109, USA.

The molecular quantum electrodynamics theory is employed to calculate the matrix element and Fermi golden rule rate for resonant transfer of electronic excitation energy between a donor and an acceptor in the vicinity of two neutral electric dipole polarizable particles, which play the role of bridging species. The emitter and absorber couple linearly to the electric displacement field via their electric dipole moments, while each mediator interacts quadratically with this field through its dynamic polarizability. This form of interaction Hamiltonian enables fourth-order perturbation theory to be used to compute the probability amplitude together with summation over 24 time-ordered diagrams representing a single virtual photon exchange between each pair of coupled particles. Read More

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December 2019

Switching plasmonic Fano resonance in gold nanosphere-nanoplate heterodimers.

Nanoscale 2019 May;11(19):9641-9653

Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.

The interference between spectrally overlapping superradiant and subradiant plasmon resonances generates plasmonic Fano resonance, which allows for attractive applications such as electromagnetically induced transparency, light trapping, and refractometric sensing with high figures of merit. The active switching of plasmonic Fano resonance holds great promise in modulating optical signals, dynamically harvesting light energy, and constructing switchable plasmonic sensors. However, structures enabling the active control of plasmonic Fano resonance have rarely been achieved because of the fabrication complexity and cost. Read More

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Ion-Induced Formation of Nanocrystalline Cellulose Colloidal Glasses Containing Nematic Domains.

Langmuir 2019 03 8;35(11):4117-4124. Epub 2019 Mar 8.

Institute of Food Nutrition and Health , ETH Zurich , 8092 Zurich , Switzerland.

Controlling the assembly of colloids in dispersion is a fundamental approach toward the production of functional materials. Nanocrystalline cellulose (NCC) is a charged nanoparticle whose colloidal interactions can be modulated from repulsive to attractive by increasing ionic strength. Here, we combine polarized optical microscopy, rheology, and small-angle scattering techniques to investigate (i) the concentration-driven transition from isotropic dispersion to cholesteric liquid crystals and (ii) salt-induced NCC phase transitions. Read More

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Controlling the Dynamics and Optical Binding of Nanoparticle Homodimers with Transverse Phase Gradients.

Nano Lett 2019 02 9;19(2):897-903. Epub 2019 Jan 9.

Department of Chemistry , The University of Chicago , Chicago , Illinois 60637 , United States.

While transverse phase gradients enable studies of driven nonequilibrium phenomena in optical trapping, the behavior of electrodynamically interacting particles in a transverse phase gradient has not been explored in detail. In this Letter we study electrodynamically interacting pairs of identical nanoparticles (homodimers) in transverse phase gradients. We establish that the net driving force on homodimers is modulated by a separation-dependent interference effect for small phase gradients. Read More

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February 2019

A New Method for Predicting Erosion Damage of Suddenly Contracted Pipe Impacted by Particle Cluster via CFD-DEM.

Materials (Basel) 2018 Sep 28;11(10). Epub 2018 Sep 28.

Department of Mechanical Engineering, Xi'an Shiyou University, Xi'an 710065, China.

A numerical study on the erosion of particle clusters in an abrupt pipe was conducted by means of the combined computational fluid dynamics (CFD) and discrete element methods (DEM). Furthermore, a particle-wall extrusion model and a criterion for judging particle collision interference were developed to classify and calculate the erosion rate caused by different interparticle collision mechanisms in a cluster. Meanwhile, a full-scale pipe flow experiment was conducted to confirm the effect of a particle cluster on the erosion rate and to verify the calculated results. Read More

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September 2018

Silica-Coated Magnetite Nanoparticles Carrying a High-Density Polymer Brush Shell of Hydrophilic Polymer.

Macromol Rapid Commun 2018 Jul 7;39(13):e1800226. Epub 2018 Jun 7.

Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 6, Göttinge, 37077, Germany.

Integrating the properties of magnetite nanoparticles (MNPs) and high-density polymer brushes in one structure requires sophisticated synthetic designs and effective chemical approaches. A simple and versatile strategy for the fabrication of hydrophilic-polymer-capped magnetite-core-silica-shell nanohybrids with well-defined structure employing reverse microemulsion technique and reversible addition-fragmentation chain transfer (RAFT) polymerization is presented. The high-density polymer brush allows precise patterning of the magnetic nanohybrids with a tunable interparticle distance ranging from 20 nm to 80 nm by controlling the polymer size. Read More

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Effects of particle size and annealing on plasmon-induced charge separation at self-assembled gold nanoparticle arrays.

Phys Chem Chem Phys 2018 Jan;20(5):3735-3740

Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.

Two-dimensional periodic Au nanoparticle arrays were constructed on TiO thin films by a micelle lithography method and seed-mediated photoelectrochemical growth. Their adjustable interparticle distance allows investigation of a particle size effect on plasmon-induced charge separation (PICS) efficiencies without interference from particle aggregation or plasmon coupling. External or internal PICS efficiencies were found to increase and decrease, respectively, with an increase in particle diameter from 25 to 38 nm. Read More

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January 2018

Synthesis of Ferrofluids Made of Iron Oxide Nanoflowers: Interplay between Carrier Fluid and Magnetic Properties.

Nanomaterials (Basel) 2017 Nov 5;7(11). Epub 2017 Nov 5.

Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, I- 44122 Ferrara, Italy.

Ferrofluids are nanomaterials consisting of magnetic nanoparticles that are dispersed in a carrier fluid. Their physical properties, and hence their field of application are determined by intertwined compositional, structural, and magnetic characteristics, including interparticle magnetic interactions. Magnetic nanoparticles were prepared by thermal decomposition of iron(III) chloride hexahydrate (FeCl₃·6H₂O) in 2-pyrrolidone, and were then dispersed in two different fluids, water and polyethylene glycol 400 (PEG). Read More

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November 2017

Off-axis electron holography of bacterial cells and magnetic nanoparticles in liquid.

J R Soc Interface 2017 10;14(135)

Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany

The mapping of electrostatic potentials and magnetic fields in liquids using electron holography has been considered to be unrealistic. Here, we show that hydrated cells of strain AMB-1 and assemblies of magnetic nanoparticles can be studied using off-axis electron holography in a fluid cell specimen holder within the transmission electron microscope. Considering that the holographic object and reference wave both pass through liquid, the recorded electron holograms show sufficient interference fringe contrast to permit reconstruction of the phase shift of the electron wave and mapping of the magnetic induction from bacterial magnetite nanocrystals. Read More

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October 2017

Calculation of the cross-sectional shape of a fibril from equatorial scattering.

J Struct Biol 2017 12 13;200(3):248-257. Epub 2017 May 13.

Northeastern University, Boston, United States. Electronic address:

An alternate formulation of helical diffraction theory is used to generate cross-sectional shapes of fibrous structures from equatorial scattering. We demonstrate this approach with computationally generated scattering intensities and then apply it to scattering data from Tobacco Mosaic Virus (TMV) and in vitro assembled fibrils of Aβ peptides. Refining the cross-sectional shape of TMV from SAXS data collected on a 26mg/ml solution resulted in a circular shape with outer diameter of ∼180Å and inner diameter of ∼40Å consistent with the known structure of TMV. Read More

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December 2017

Mechanically tunable sub-10 nm metal gap by stretching PDMS substrate.

Nanotechnology 2017 Jan 11;28(7):075301. Epub 2017 Jan 11.

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.

Manipulating light in sub-10 nm or subnanometer metal nanogaps is crucial to study the strong interaction between electromagnetic waves and matters. However, the fabrication of metallic nanogaps with precisely controlled size and high-throughput still remains a challenge. Here, we developed an approach to actively control the gap distance between adjacent metal nanoparticles from 140 nm to sub-10 nm or even 0 nm via mechanical stretching process. Read More

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January 2017

A generalized quantitative interpretation of dark-field contrast for highly concentrated microsphere suspensions.

Sci Rep 2016 10 13;6:35259. Epub 2016 Oct 13.

Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland.

In X-ray grating interferometry, dark-field contrast arises due to partial extinction of the detected interference fringes. This is also called visibility reduction and is attributed to small-angle scattering from unresolved structures in the imaged object. In recent years, analytical quantitative frameworks of dark-field contrast have been developed for highly diluted monodisperse microsphere suspensions with maximum 6% volume fraction. Read More

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October 2016

Rotation of two trapped microparticles in vacuum: observation of optically mediated parametric resonances.

Opt Lett 2015 Oct;40(20):4751-4

We demonstrate trapping and rotation of two mesoscopic particles in vacuum using a spatial-light-modulator-based approach to trap more than one particle, induce controlled rotation of individual particles, and mediate interparticle separation. By trapping and rotating two vaterite particles, we observe intensity modulation of the scattered light at the sum and difference frequencies with respect to the individual rotation rates. This first demonstration of optical interference between two microparticles in vacuum leads to a platform to potentially explore optical binding and quantum friction effects. Read More

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October 2015

Molecular Assembly of Wheat Gliadins into Nanostructures: A Small-Angle X-ray Scattering Study of Gliadins in Distilled Water over a Wide Concentration Range.

J Agric Food Chem 2015 Oct 24;63(39):8715-21. Epub 2015 Sep 24.

Division of Agronomy and Horticultural Science, Graduate School of Agriculture, Kyoto University , Gokasho, Uji, Kyoto 611-0011, Japan.

Gliadin, one of the major proteins together with glutenin composing gluten, affects the physical properties of wheat flour dough. In this study, nanoscale structures of hydrated gliadins extracted into distilled water were investigated primarily by small-angle X-ray scattering (SAXS) over a wide range of concentrations. Gliadins are soluble in distilled water below 10 wt %. Read More

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October 2015

Giant local circular dichroism within an asymmetric plasmonic nanoparticle trimer.

Sci Rep 2015 Feb 3;5:8207. Epub 2015 Feb 3.

Key Lab of Micro-/Nano- Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China.

We investigated the near-field response in silver nanoparticle aggregates to the excitation of circular polarized light. In a right-angle trimer system, the local field intensity excited by right-hand circularly polarized light is almost one thousand times larger than the left-hand case. By analyzing the polarization and phase of the local field in plasmonic hotspots, we found this local circular dichroism is originated from the near-field interference excited by orthogonal polarized incident lights. Read More

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February 2015

Enhancing nanoparticle electrodynamics with gold nanoplate mirrors.

Nano Lett 2014 May 22;14(5):2436-42. Epub 2014 Apr 22.

The James Franck Institute, The University of Chicago , 929 East 57th Street, Chicago, Illinois 60637, United States.

Mirrors and optical cavities can modify and enhance matter-radiation interactions. Here we report that chemically synthesized Au nanoplates can serve as micrometer-size mirrors that enhance electrodynamic interactions. Because of their plasmonic properties, the Au nanoplates enhance the brightness of scattered light from Ag nanoparticles near the nanoplate surface in dark-field microscopy. Read More

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Self crowding of globular proteins studied by small-angle x-ray scattering.

Biophys J 2014 Feb;106(4):895-904

Department of Biology, University of Utah, Salt Lake City, Utah.

Small-angle x-ray scattering (SAXS) was used to study the behavior of equine metmyoglobin (Mb) and bovine pancreatic trypsin inhibitor (BPTI) at concentrations up to 0.4 and 0.15 g/mL, respectively, in solutions also containing 50% D2O and 1 M urea. Read More

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February 2014

Specific and sensitive colorimetric detection of Al3+ using 5-mercaptomethyltetrazole capped gold nanoparticles in aqueous solution.

Talanta 2014 Feb 13;119:306-11. Epub 2013 Nov 13.

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.

Contamination of food and drinking water by health-risk levels of Al(3+) calls for convenient assays. Here, we report a method to visibly detect Al(3+) at room temperature. Firstly, the chelating ligand of 5-mercaptomethyltetrazole (MMT) was synthesized and modified on the surface of AuNPs through the strong Au-S interaction to form a MMT-AuNP probe, which can remain well-dispersed and stable in an aqueous solution for a long time. Read More

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February 2014

Engineering the plasmonic optical properties of cubic silver nanostructures based on Fano resonance.

J Chem Phys 2013 Oct;139(16):164713

Electronic Materials Research Laboratory (EMRL), Key Laboratory of Education Ministry, International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China.

The plasmonic optical properties of nanostructures including a dimer, a linear chain, a T-shaped nanostructure, and a 2D array consisting of Ag nanocubes have been investigated using the discrete dipole approximation method. The simulation results indicate that both the interparticle gap and polarization have an important impact on far-field and near-field characteristics. With decreasing interparticle distance for four nanostructures, the plasmon resonance peak is monotonically red-shifted and the electric intensity enhancement factor increases rapidly due to increased interparticle coupling interaction. Read More

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October 2013

Nanomagnetism study of highly-ordered iron oxide nanocrystal assemblies fabricated by the Langmuir-Blodgett technique.

Phys Chem Chem Phys 2013 Sep;15(35):14689-95

Group of Ionic Liquids Clean Process and Energy-saving, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China.

Iron oxide nanocrystals are ideal building blocks for the construction of flexible nanodevices whose performance can be modulated by controlling the morphology of isolated particles and their organizational form. This work demonstrates the fabrication of high quality Langmuir-Blodgett (LB) nanocrystal assemblies with limited overlapping and higher coverage by systemically and combinatorially optimizing the parameters of compression pressure and quantity of spread nanocrystals. Monodispersed iron oxide nanocrystals with a diameter of 11. Read More

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September 2013

Alignment of graphene sheets in wax composites for electromagnetic interference shielding improvement.

Nanotechnology 2013 Mar 1;24(11):115708. Epub 2013 Mar 1.

Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, People's Republic of China.

Rapid advancements in carbon-based fillers have enabled a new and more promising platform in the development of electromagnetic attenuation composites. Alignment of fillers in composites with specific structures and morphologies has been widely pursued to achieve high performance based on taking advantage of unique filler characteristics. In this work, few-layer graphene (FLG), obtained from direct exfoliation of graphite, was fabricated into paraffin wax to prepare FLG/wax composites and investigate their electromagnetic interference (EMI) shielding performance. Read More

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How an interacting many-body system tunnels through a potential barrier to open space.

Proc Natl Acad Sci U S A 2012 Aug 6;109(34):13521-5. Epub 2012 Aug 6.

Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg, Germany.

The tunneling process in a many-body system is a phenomenon which lies at the very heart of quantum mechanics. It appears in nature in the form of α-decay, fusion and fission in nuclear physics, and photoassociation and photodissociation in biology and chemistry. A detailed theoretical description of the decay process in these systems is a very cumbersome problem, either because of very complicated or even unknown interparticle interactions or due to a large number of constituent particles. Read More

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Subgroup decomposition of plasmonic resonances in hybrid oligomers: modeling the resonance lineshape.

Nano Lett 2012 Apr 29;12(4):2101-6. Epub 2012 Mar 29.

Data Storage Institute, (A*STAR) Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608.

Plasmonic resonances with a Fano lineshape observed in metallic nanoclusters often arise from the destructive interference between a dark, subradiant mode and a bright, super-radiant one. A flexible control over the Fano profile characterized by its linewidth and spectral contrast is crucial for many potential applications such as slowing light and biosensing. In this work, we show how one can easily but significantly tailor the overall spectral profile in plasmonic nanocluster systems, for example, quadrumers and pentamers, by selectively altering the particle shape without a need to change the particle size, interparticle distance, or the number of elements of the oligomers. Read More

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Optical properties of porous anodic alumina membrane uniformly decorated with ultra-thin porous gold nanoparticles arrays.

J Nanosci Nanotechnol 2011 Feb;11(2):941-52

Department of Physics, Chonnam National University, Gwangju 500-757, South Korea.

In this paper, we directly develop a facile method to decorate a modified porous anodic alumina membrane (PAA) with an ultrathin porous film of gold nanoparticles with sub-gaps less than 25 nm and particle size less than 40 nm on the top surface and Au nanoparticles uniformly attached to the pore walls as well as the bottom of the pores, utilizing radio-frequency magnetron sputtering. The size as well as the interparticle distance of the gold nanostructures is adjusted by changing the structural properties of PAA membrane and the sputtering time. According to the measured reflection spectra, the saturation of interference color is significantly enhanced. Read More

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February 2011

Optical impedance matching using coupled plasmonic nanoparticle arrays.

Nano Lett 2011 Apr 16;11(4):1760-5. Epub 2011 Mar 16.

Center for Nanophotonics, FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.

Silver nanoparticle arrays placed on top of a high-refractive index substrate enhance the coupling of light into the substrate over a broad spectral range. We perform a systematic numerical and experimental study of the light incoupling by arrays of Ag nanoparticle arrays in order to achieve the best impedance matching between light propagating in air and in the substrate. We identify the parameters that determine the incoupling efficiency, including the effect of Fano resonances in the scattering, interparticle coupling, as well as resonance shifts due to variations in the near-field coupling to the substrate and spacer layer. Read More

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