A5049910662- Electromagnetic Scattering and Analysis
- Electromagnetic Simulation and Numerical Methods
- Advanced Antenna and Metasurface Technologies
- Plasmonic and Surface Plasmon Research
- Electromagnetic Compatibility and Measurements
- Antenna Design and Analysis
- Metamaterials and Metasurfaces Applications
- Microwave Engineering and Waveguides
- Gold and Silver Nanoparticles Synthesis and Applications
- Antenna Design and Optimization
- Soil Moisture and Remote Sensing
- Microwave Imaging and Scattering Analysis
- Geophysical Methods and Applications
- Numerical methods in engineering
- Optical Coatings and Gratings
- Photonic Crystals and Applications
- Radio Wave Propagation Studies
- Nanocluster Synthesis and Applications
- Photonic and Optical Devices
- Advanced biosensing and bioanalysis techniques
- Advanced Fiber Optic Sensors
- Electromagnetic Compatibility and Noise Suppression
- Ocean Waves and Remote Sensing
- Radar Systems and Signal Processing
- Electric Motor Design and Analysis
Universidade de Vigo
2015-2024
Universidad de Extremadura
2010-2024
Ikerbasque
2016
Centro Tecnolóxico de Telecomunicacións de Galicia
2012
The Ohio State University
2003
Surfactant-assisted seeded growth of metal nanoparticles (NPs) can be engineered to produce anisotropic gold nanocrystals with high chiroptical activity through the templating effect chiral micelles formed in presence dissymmetric cosurfactants. Mixed adsorb on nanorods, forming quasihelical patterns that direct into NPs pronounced morphological and optical handedness. Sharp wrinkles lead plasmon modes dissymmetry factors (~0.20). Through variation dimensions wrinkles, properties tuned...
Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of optical near field produced by collective electron excitations -plasmons- in nanostructured metal surfaces gives rise dramatic increase many orders magnitude intensities from neighboring molecules. This effect strongly depends on detailed geometry and composition plasmon-supporting...
A robust and reproducible methodology to prepare stable inorganic nanoparticles with chiral morphology may hold the key practical utilization of these materials. An optimized growth method fourfold twisted gold nanorods is described herein, where amino acid cysteine used as a dissymmetry inducer. Four tilted ridges are found develop on surface single-crystal upon repeated reduction HAuCl
A formulation based on the high frequency asymptotic principles of physical optics is developed for analyzing scattering by relatively arbitrary open-ended waveguide cavities containing complex interior terminations. magnetic field integral equation (MFIE) obtained equivalent currents cavity walls and solved using an iterative (IPO) algorithm which iteratively applies to account multiple reflections inside cavity. The number iterations required convergence related expected important...
Advances in the field of nanoplasmonics are hindered by limited capabilities simulation tools dealing with realistic systems comprising regions that extend over many light wavelengths. We show optical response unprecedentedly large can be accurately calculated using a combination surface integral equation (SIE) method moments (MoM) formulation and an expansion electromagnetic fields suitable set spatial wave functions via fast multipole methods. start critical review volume versus methods,...
The thermoresponsive optical properties of Au nanorod-doped poly(N-isopropylacrylamide) (Au NR-pNIPAM) microgels with different NR payloads and aspect ratios are presented. Since the volume phase transition pure pNIPAM is reversible, response reversibility NR-pNIPAM hybrids systematically analyzed. Besides, extinction cross-section near-field enhancement simulations for NR-microgel performed using a new numerical method based on surface integral equation moments formulation (M3 solver)....
Palladium nanoparticles (NPs) have received tremendous attention over the years due to their high catalytic activity for various chemical reactions. However, unlike other noble metal such as Au and Ag NPs, they exhibit poor plasmonic properties with broad extinction spectra less scattering efficiency, thus limiting applications in field of plasmonics. Therefore, it has been challenging integrate tunable strong into Pd nanoparticles. Here we show that Au@Pd nanorods (NRs) relatively narrow...
In Holliday et al. (1995, 1996), the iterative forward-backward (FB) method has been proposed to solve magnetic field integral equation (MFIE) for smooth one-dimensional (1-D) rough surfaces. This proved be very efficient, converging in a small number of iterations. Nevertheless, this solution becomes unstable when some obstacle, like ship or large breaking wave, is included original problem. paper, we propose new method: generalized (GFB) such kinds complex problems. The approach formulated...
An efficient hybrid MPI/OpenMP parallel implementation of an innovative approach that combines the Fast Fourier Transform (FFT) and Multilevel Multipole Algorithm (MLFMA) has been successfully used to solve electromagnetic problem involving 620 millions unknowns.The MLFMA-FFT method can deal with extremely large problems due its high scalability reduced computational complexity.
We present a surface integral equation (SIE) to model the electromagnetic behavior of metallic objects at optical frequencies. The electric and magnetic current combined field considering both tangential normal equations is applied. SIE solved by using method-of-moments (MoM) formulation. SIE-MoM approach applied only on material boundary surfaces interfaces, avoiding cumbersome volumetric discretization surrounding space required in differential-equation formulations. Some canonical...
The performance of most widespread surface integral equation (SIE) formulations with the method moments (MoM) are studied in context plasmonic materials.Although not yet optics, SIE-MoM approaches bring important advantages for rigorous analysis penetrable bodies.Criteria such as accuracy near and far field calculations, iterative convergence reliability addressed to assess suitability these plasmonics.
Gold nanorod supercrystals have been widely employed for the detection of relevant bioanalytes with limits ranging from nano- to picomolar levels, confirming promising nature these structures biosensing. Even though a relationship between height supercrystal (i.e., number stacked layers) and enhancement factor has proposed, no systematic study reported. In order tackle this problem, we prepared gold varying numbers layers analyzed them extensively by atomic force microscopy, electron...
Hybrid colloidal nanocomposites comprising polystyrene beads and plasmonic gold nanostars are reported as multifunctional optical nanoprobes. Such self-assembled structures excellent Raman enhancers for bioapplications they feature plasmon modes in the near-infrared "first biological transparency window". In this proof of concept study, we used 4-mercaptobenzoic acid a Raman-active molecule to optimize density on beads, improving SERS performance thereby allowing vitro cell culture imaging....
Optical connects will become a key point in the next generation of integrated circuits, namely upcoming nanoscale optical chips. In this context, nano-optical wireless links using nanoantennas have been presented as promising alternative to regular plasmonic waveguide links, whose main limitation is range propagation due metal absorption losses. paper we present complete design high-capability nanolink matched directive nanoantennas. It be shown how use clearly enhances capability link,...
Gold nanostars display strong electromagnetic field enhancement at their tips, and tip plasmon resonances can be tuned within the visible near-infrared, which has been applied toward plasmonic molecular sensing. However, sensitivity further increased by linking gold to other nanoparticles thereby inducing creation of hot spots. We report controlled formation core–satellite assemblies comprising a central nanostar with spheres adsorbed tips via Raman active linkers. Surface-enhanced...
The development of novel, highly efficient, reliable, and robust surface enhanced Raman scattering (SERS) substrates containing a large number hot spots with programmed size, geometry, density is extremely interesting since it allows the sensing numerous (bio-)chemical species. Herein, an easy to fabricate, label-free SERS platform based on metal nanoparticles (NPs) thin-film developed by layer-by-layer growth mediated polyelectrolytes. A systematic study effect NP composition as well...
An efficient parallel implementation of the multilevel fast multipole algorithm-fast Fourier transform (MLFMA-FFT) has been successfully used to solve an electromagnetic problem involving one billion unknowns, which indeed becomes largest solved with surface integral-equation approach up now. In this paper, we present a deep review challenging execution, focusing on details step by step, aim describing different stages algorithm and analyzing its overall performance.
A surface integral equation-method of moments (SIE-MoM) approach is presented for the solution multiple homogeneous penetrable bodies. The problem formulated using multiregion (MR) piecewise vector basis functions defined uniformly on boundary surfaces, interfaces, and line junctions. MR bases are oriented implicitly satisfying conditions. Their use greatly simplifies formulation, thereby implementation, arbitrary complex composite problems having Moreover, generation involves a negligible...
Abstract Chiral metal nanoparticles (NPs) offer a powerful means of inducing and harnessing optical activity. However, due to the incomplete knowledge underlying growth mechanisms, there is still limited control over achievable morphological detail and, consequently, resulting Therefore, theoretical modeling needed guide experimental development toward optimizing plasmonic chiroptical response. Toward filling this gap, herein an extensive parametric analysis presented, via...
An efficient parallel implementation of the Fast Multipole Method (FMM) combined with fast Fourier transform (FFT) is presented in this paper. The good scaling properties FMM-FFT, a smart parallelization strategy, has been shown to be very effective when using large supercomputers. A challenging problem more than 150 million unknowns solved, demonstrating that proposed FMM-FFT constitutes real alternative frequently used multilevel approaches, such as Multilevel FMM (MLFMA). Even...
A surface integral equation together with the multilevel fast multipole algorithm is successfully applied to and accurate resolution of plasmonic problems involving a large number unknowns. The absorption, scattering, extinction efficiencies several gold spheres increasing size are efficiently obtained solving electric magnetic current combined-field equation. numerical predictions compared reference analytic results demonstrate accuracy, suitability, capabilities this approach when dealing...
Novel plasmonic thin films based on electrostatic layer-by-layer (LbL) deposition of citrate-stabilized Au nanoparticles (NPs) and ammonium pillar[5]arene (AP[5]A) have been developed. The supramolecular-induced LbL assembly the yields formation controlled hot spots with uniform interparticle distances. At same time, this strategy allows modulating density dimensions aggregates, therefore optical response, film number AuNP-AP[5]A cycles. Characterization hybrid platforms as a function cycles...
A surface integral equation (SIE) formulation is applied to the analysis of electromagnetic problems involving three-dimensional (3D) piecewise homogenized left-handed metamaterials (LHM). The resulting equations are discretized by well-known method moments (MoM) and solved via an iterative process. unknowns defined only on interfaces between different media, avoiding discretization volumes surrounding space, which entails a drastic reduction in number arising numerical equations. Besides,...
Gold nanostars as a photocatalyst perform better than rods and cubes.
Abstract|It is a proven fact that The Fast Fourier Transform(FFT) extension of the conventional Multipole Method (FMM)reduces matrix vector product (MVP) complexity and preservesthe propensity for parallel scaling single level FMM. In thispaper, an e–cient strategy nested variation FMM-FFT algorithm reduces memory requirements presented.The solution provided by this implementation challengingproblem with more than 0.5 billion unknowns has constituted worldrecord in computational...