A5015819679- Electromagnetic Scattering and Analysis
- Electromagnetic Simulation and Numerical Methods
- Advanced Antenna and Metasurface Technologies
- Metamaterials and Metasurfaces Applications
- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Electromagnetic Compatibility and Measurements
- Antenna Design and Analysis
- Numerical methods in engineering
- Microwave Engineering and Waveguides
- Antenna Design and Optimization
- Optical Coatings and Gratings
- Nanocluster Synthesis and Applications
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Soil Moisture and Remote Sensing
- Advanced biosensing and bioanalysis techniques
- Advanced Numerical Methods in Computational Mathematics
- Advanced Fiber Optic Sensors
- Radio Wave Propagation Studies
- Orbital Angular Momentum in Optics
- Copper-based nanomaterials and applications
- Advanced Measurement and Metrology Techniques
- Radio Astronomy Observations and Technology
- Near-Field Optical Microscopy
Universidad de Extremadura
2015-2024
Polytechnic University of Turin
2024
Universidade de Vigo
1999-2024
Complejo Hospitalario de Cáceres
2011-2016
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
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...
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...
A limiting factor of solvent-induced nanoparticle self-assembly is the need for constant sample dilution in assembly/disassembly cycles. Changes concentration alter kinetics subsequent assembly process, optical signal recovery. Herein, we show that upon confining hydrophobic nanoparticles permeable silica nanocapsules, number participating cyclic aggregation remains despite bulk changes solution, leading to highly reproducible plasmon band shifts at different solvent compositions.
Chiral plasmonics is a rapidly developing field where breakthroughs and unsolved problems coexist. We have recently reported binary surfactant-assisted seeded growth of chiral gold nanorods (Au NRs) with high chiroptical activity. Such seeded-growth process involves the use cosurfactant that induces micellar helicity, in turn driving transition from achiral to Au NRs, both morphological optical points view. report herein detailed study on transitions, which reveals intermediate states were...
Fabrication and transmission of plasmonic chirality is a rapidly developing area research. While nanoscale reasonably well explored, research on intrinsically chiral nanostructures, that has ramifications to origin homochirality, still in its infancy. Herein, we report the synthesis dog-bone shaped gold nanostructures using cationic surfactant with excess ascorbic acid. Chiral growth attributed specific binding structure breaking ability The controlled assembly particles facilitated tuning...
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.
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...
Surface-enhanced Raman spectroscopy (SERS) microfluidic chips for label-free and ultrasensitive detection are fabricated by integrating a plasmonic supercrystal within channels. This platform allows the uniform infiltration of analytes supercrystal, reaching so-called hot spots. Moreover, state-of-the-art simulations performed using large-scale models demonstrate that excellent SERS response is due to hierarchical nanoparticle organization, interparticle separation (IPS), presence defects....
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...