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We demonstrate that radial anisotropy can be employed to tune effectively the spectral positions of electric resonances of nanoparticles, which enables flexible overlapping of electric and magnetic dipoles of various numbers and thus leads to unidirectional forward superscattering. We further reveal that through adjusting the radial anisotropy parameters, electric and magnetic resonances of higher...
Nanoantennas have demonstrated unprecedented capabilities for manipulating the intensity and direction of light emission over a broad frequency range. The directional beam steering offered by nanoantennas has important applications in areas including microscopy, spectroscopy, quantum computing, and on-chip optical communication. Although the Kerr effect has been explored to control the far-field radiation...
Various metallic nanostructures have been proposed to effectively utilize surface plasmon polaritons (SPPs) to improve the performance of optical devices such as solar cells, antennas, sensors, and light emission devices. With the progress in the research on SPP-based devices, the requirements for better materials have been increasing. Conventional SPP materials such as silver and gold have problems...
Since Ashkin and colleagues reported the first stable three-dimensional (3D) optical trapping, or optical tweezers, created using radiation pressure from a single focused laser beam, optical tweezers have become an important tool for research in the fields of biology, physical chemistry and soft matter physics. Plasmonic nanoparticles have attracted increased attentions in recent years due to various...
Conventional optical tweezers handle non-absorptive (transparent) particles, and the force exerted to the particle is proportional to the intensity of the trapping laser. Recently, some works on selective trapping/manipulation of absorptive particles based on resonance effects have been reported. Some years ago, our research group found that the use of an ultra-short pulsed laser as a trapping light...
Plasmonic devices have attracted huge attention from the scientific community over the last decade owing to their ability to render highly localized electromagnetic fields in the visible and near-infrared, such that numerous cutting-edge nanotechnology applications are arising that hinder on this unique property. Amongst them, surface-enhanced Raman scattering (SERS) is a spectroscopic technique that...
Graphene, with its unique electrical, optical, mechanical, and chemical properties, attracts enormous research interests from various fields since it was first exfoliated from bulk graphite in 2004. It is believed that the potential of graphene in photonic and optoelectronics is significant, as it exhibits both extraordinary electronic and optical properties. Especially, graphene is considered as...
Electron energy loss spectroscopy is one of the most important and versatile tools for experiments at the frontier of plasmonics research. In this short paper, we present a new method based on Transformation optics to analyze the electromagnetic response of plasmonic particles under electron beam excitation. We present analytical results for the electron energy loss and photon scattering spectra of...
Transient absorption spectroscopy has been extensively used in recent years to examine the temporal response of isolated nanoparticles (NPs) to the absorption of light [1]. These studies are largely based on the use of the surface plasmon resonance (SPR) to monitor characteristics of the NP such as electronic and lattice temperature, shape and morphology as a function of time. In the case of extended...
We investigate the spectral properties of a one-dimensional photonic crystal with the structural defect conjugated to the nanocomposite layer. The nanocomposite consists of spherical silver particles dispersed in the matrix. We demonstrate the possibility of implementing the hybrid state formed by the interaction between the optical Tamm and defect modes. It is shown that the hybrid state resonance...
During the last decade, many efforts have been made to develop techniques to integrate nanostructures in functional matrices. This activity, mainly boosted by advances in nanofabrication, has enabled the development of elegant methods for the development of planar nanodevices. However, the design and implementation of embedded three-dimensional (3D) nanoarchitectures with tunable spatial orientation...
We propose and demonstrate a new class of all-dielectric metamaterial superlens constructed from 3D assembly of high-index nanoparticles (TiO2, ZrO2, Si). The fundamental physics lies in the unusual high efficiency of direct conversion of evanescent waves into propagation waves by the composite media. In Figure 1(a) 3D full wave FDTD simulation was presented for a conventional homogenous material...
Laser ablation in liquids is now commonly used to produce colloidal nanoparticles (NPs) that have found numerous applications in different areas. In the experiments, NPs of different materials can be rather easily produced by using laser systems with various pulse durations, shape, wavelengths, and fluence. Here, we focus our attention on metal nanoparticles produced by ultra-short laser pulses.
In this study, a potential biomaterial detection technology was successfully developed based on giant magnetoresistance (GMR) sensors. The GMR sensors were performed using [Co(1.5 nm)/Cu(x)]20 multilayer structures (x = 0.8, 0.9 and 1.0 nm) fabricated by DC magnetron sputtering. The X-ray diffraction (XRD) patterns showed that Co/Cu film multilayer has a high degree of crystallinity with a single...
Plasmons, the collective oscillation of electrons in conducting materials, provide a powerful platform for manipulating light-matter interactions in the subwavelength scale. Recently, graphene plasmons have attracted much attention [1]. The low-loss intrinsic plasmons in graphene exhibit small spatial extensions and remarkable enhancement of local electromagnetic fields. Along with the tunability,...
The main idea of the effective susceptibility concept consists in calculation of the linear response of the nanosystem as a single whole to the external field. The effective susceptibility is derived from a self-consistent integral equation for the local field. The electrodynamic interactions between embedded particles as well as interactions between the particles and matrix are taken into account...
Optoelectronic devices can harvest, control and detect light and they are highly important in developing solar cells, sensors and lasers. Recently, the emergence of plasmonics has raised interest to examine the optical nanoantenna properties based on plasmonic metal nanostructures, which shows various promising applications including plasmonic chips, light generation, biosensing, and subwavelength...
By considering parity-time (PT) symmetric plasmonic chains, an array of plasmonic nanoparticles coated alternatively by gain-loss balanced dielectrics, we demonstrate that it supports topological edge states with quantized Zak phase when there is no exceptional point in the entire Brillouin zone (BZ). We show that the coupled dipole equation of the system can be reduced to a 2 by 2 Eigenvalue problem,...
By considering an array of plasmonic nanoparticles coated alternatively by gainloss balanced dielectrics, we demonstrate that a PT-symmetric chain can support topological edge modes with quantized Zak phases if the bulk modes for all real Bloch's wavevectors are in the PT symmetric unbroken phase. We show that the coupled dipole equation of the system can be reduced to a 2 × 2 Eigenvalue problem,...
The electromagnetic radiation has given rise to a number of diagnostics techniques covering a broad range of the wave lengths that are of vital importance for materials science. In particular, their non-destructive character and possibility to perform time-resolved studies under various external conditions (temperature, ambient, electrical and/or magnetic fields, etc.) render these techniques very...
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