Papers by Keyword: Plasmon Resonance

Abstract: Pulsed laser ablation in liquid (PLAL) is considered a relatively fast, simple to manipulate, cost-effective abraoch, and enables the fabrecation of multiscale micro-nanostructures in one step, facilitating the fabrication process. Copper nanoparticles solution was prepared by PLAL technique using Nd:YAG laser in deionized water at (532 nm), (1000 pulse), and the energies (700 mJ, 800 mJ, 900 mJ, and 1000 mJ) with a fixed distance between the laser source and the sample, fixed amount of liquid, and the liquid rise above the copper was (5 mm). The effect of the excess of the laser energy in the preparation process was tested by analyzing the optical properties of the fabrecated samples by UV-Visible spectrophotometer, SEM, XRD, and EDX measurements.

Abstract: The presented study in the field of optical area is about receiving polymer new materials in the way of doping a small amount of fullerene С_60. Under the method of preparing samples it is revealed characteristics of an interaction between polymer components and doping materials. Significant absorption of ultraviolet radiation by studied samples at the certain concentration of the doping material is presented in the result of the optical study. It is shown that metal-fullerene nanostructures which are on the polymer surface call surface resonance of plasmon absorption.

Abstract: Enhancement of surface-enhanced Raman scattering (SERS) by metal nanoparticles has attracted considerable interest on account of their widespread popularity of SERS-based measurements and devices ranging from life science until materials science. Current study focuses on noble metal SERS substrates with attempting to achieve high and enhanced effect by describe a plasmon-enhanced SERS substrate based on gold-silver, alloy-coated co-polymer (methyl methacrylate-styrene) colloidal sphere. Copolymer was synthesised via surfactant-free emulsion polymerization and was successfully produced a homogeneous colloidal spheres. The homogenous spheres of copolymer would promote periodic array upon fabrication and more, introducing the copolymer medium had improved the thermal degradation of the material compare to single polymer. Gold-silver alloy nanospheres was synthesised via one pot reduction method using citrate stabilizer. The nanoalloy obtained are well within the nanoscale domain (<100 nm) supported by the maximum surface plasmon resonance peak at 436 nm using UV-Visible spectroscopy. The perfect combination of our proposed alloy nanoparticles and copolymer present an ability to enhance Raman scattering by higher than 90 %. The region of high electron density of the substrate is expected to develop a new opportunities for SERS detections in wide analytical area.

Abstract: We have reported on the fluorescence behaviors of Rhodamine 6G with the palladium-coat gold nanorods in dichlormethane solution and in polymethylmethaceylate thin film. By monitoring the emission intensity of these samples, they show the enhancement of fluorescence intensity through the optical effect known as a plasmon resonance energy transfer. The enhancement intensity of fluorescence is enhanced up to 1.6 fold for the sample solution and 1.4 fold for the sample thin film.

Abstract: The review reports on the results of our research work on nanostructured metal films onto porous silicon. Principal steps of the techniques allowing fabrication of metal films completely inheriting morphological pattern of different types of porous silicon are presented. It is shown, that giving of the nanostructured pattern to metal films by means of porous silicon template opens their new structural, optical, mechanical and electrical properties, which can be successfully applied in nanoelectronics and biomedicine, particularly including devices based on superconductivity effect, SERS analysis with picomolar sensitivity and transdermal drug delivery by electroporation.

Abstract: This work presents a broadband optical transparency structure consisting of a metal film perforated by an array of strip cavities. We theoretically demonstrate the metal film with side-coupled grooves system in model structure by the coupled model theory. The transparent light with a great bandwidth is obtained as a result of the tunneling and the resonance effect of the cavities by employing the finite-difference time-domain method simulation. By changing the parameter of the grooves in the structure, the transparency property shows a great adjustment in both wavelength and bandwidth. These structures have potential applications for transparent conductor devices.

Abstract: A modeling study on energy absorption and transport in an isolated nanoshell and aggregates of nanoshells under localized surface plasma resonance (SPR) conditions is presented. A comprehensive model for multi-scattering of electromagnetic waves by a cluster of multilayered nanoshells is developed, which applies the Wigner-Eckart theorem for the calculation of the total scattering cross sessions of nanoshell aggregates. Absorption by an isolated nanoshell and by nanoshell clusters is studied using the model. Results show that the inter-nanoshell coupling results in strong field enhancement near the particle surface. Energy absorption in a nanoshell can be tuned by varying the structural parameters of the nanoshell. Smaller particles are more absorbing than the large ones, other conditions being equal. Because of the presence of a dielectric cavity, the radial distribution of the absorbed power in the metal shell may differ from the classical skin depth phenomena. The interaction among particles in close proximity causes the energy absorption efficiency and the resonance position of a nanoshell cluster to differ from those of an isolated nanoshell.

Abstract: ion plasma sputtering, carbon diamond-like films, modification, metal nanoclusters, optical properties, plasmon resonance.

Abstract: The nanostructure of bimetallic Au/Pd particles was fabricated to investigate their surface plasmon (SP) dynamics and local field factor. The SP dynamics was detected according to the structure, electric dipole and multipole electrical quadrupole moment. It was found that the symmetric coupling red shifts decreased obviously with the increase of the shell thickness and the nanoparticle size, and the absorption efficiencies of the nanostructure depended on the SP resonance frequency. The waves of surface plasmon Pd/Au are achieved by gradient of electrons density between interface and shell layer. The dipole couple and electrical quadrupole moment make the plasmonic anisotropy related to transition of electron energy band. The FWHM under collective plasmonic enhancement has been found to enlarge with rise of radius ratio.Moreover, the SP resonance and the local field were measured with annular limited optical distribution in terms of dipole resonance mode and resonance frequency. The resonance scattering has been changed inspite of the Au/Pd deformation and the collective plasmon enhancement. Besides, the single particle in Z direction went up with the particle dimension. The solid structures of the Au/Pd Core/shell nanoparticles were measured by TEM and EDS

Abstract: Experimental results are presented on the ablation of copper and brass targets in a liquid environment: ethanol, acetone, or water by irradiation with either a pulsed copper vapour laser (0.51 μm) or a pulsed Nd:YAG laser (1.06 μm). The ablated material was ejected into the surrounding liquid as nanoparticles of average size 20 nm. The nanoparticle composition depends on the nature of the liquid. Ablation of 60%Cu, 40%Zn brass in ethanol results in formation of core-shell nanoparticles. Brass nanoparticles were characterized by a well-defined plasmon peak at 510-520 nm.