Plasmon nanostructured materials

Ray, K., Badugu, R., and Lakowicz, J. R. (2007). Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures. Chemistry of Materials 19 5902-5909. 

Plasmonic nanostructures that are materials consisting of noble metal nanoparticles with sizes of 1-100 nm are known as specific substrates for surface enhanced Raman scattering and luminescence enhancement [1-4]. These effects are stimulated by the localized surface plasmon absorption (LSPA) and may be controlled by the change of metal nanoparticle sizes, their concentration and a substrate choice [5]. New opportunities for surface-enhanced effect realization and optimization are now discussed in connection with bimetallic nanostructures [6]. At the technological aspect one of the simplest types of a binary nanostructure is a stratified system made of two different monolayers, each is consisted of definite metal nanoparticles. The LSPA properties of these binary close-packed planar nanostructures are the subject of the paper. 

The detection of DNA hybridization using electrochemical readout is particularly attractive for the development of clinical diagnostics. The use of nanostructured materials in electrical detection for biomolecular sensing offers unique opportunities for electrochemical transduction of DNA sensing events. Tian and co-workers [175] have reported that PANI/Gold nanoparticle multilayer films electrocatalyze the oxidation of nicotinamide adenine dinucleotide (NADH) and detect DNA hybridization by both an electrochemical method and by surface plasmon enhanced fluorescence... 

This factor is taken into account in (3.5)-(3.8) above, but it can have an even greater importance in nonlinear effects, since the second-order and third-order nonlinear optical coefficients, and respectively, are affected by factors and /, respectively, as compared with the bulk material of the nanoparticle. Hence, for large /, a nanostructured material can have a larger optical nonlinearity than its bulk constituents. For typical semiconductor-doped matrices, > and /< 1. However, particularly strong local-field enhancements are observed for metal nanoparticles in the vicinity of the plasmon resonance [3.75]. 

Apart from these few examples, most nanostructured materials are synthetic. Empirical methods for the manufacture of stained glasses have been known for centuries. It is now well established that these methods make use of the diffusion-controlled growth of metal nanoparticles. The geometrical constraints on the electron motion and the electromagnetic field distribution in noble-metal nanoparticles lead to the existence of a particular collective oscillation mode, called the plasmon oscillation, which is responsible for the coloration of the material. It has been noticed recently that the beautiful tone of Maya blue, a paint often used in Mesoamer-ica, involves simultaneously metal nanoparticles and a superlattice organization [3.1]. 

For efficient coupling between a photon wave vector and free electrons in a material, the specific shape and size of nanostructures, the so-caUed plasmonic nanostructures, should be prepared to host LSPR. In order to achieve LSPR in... 

Xia, Y. and Halas, N.J. (2005) Shape-controlled synthesis and surface plasmonic properties of metallic nanostructures. Materials Research Bulletin, 30, 338-48. 

The ultrafast imaging of plasmoiuc excitations at a metal/vacuum interface is particularly well suited for TR-PEEM studies. " In the following, we will describe the TR-PEEM imaging of localized and propagating plasmonic modes at Ag/vacuum interfaces. Although TR-PEEM is frequently applied in studies of plasmonic phenomena in Ag films, the method is broadly applicable to the imaging of spatiotemporal dynamics of coherent fields and electroiucally excited states in complex nanostructured materials. 

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

Localized plasmon resonance on noble metal nanostructures Noble metal nanostructures exhibit a strong UV visible extinction band with its peak position affected by the dielectric constant and thickness of the material surrounding the nanostructures 7,11 13... 

Abstract Optical techniques for three-dimensional micro- and nanostructuring of transparent and photo-sensitive materials are reviewed with emphasis on methods of manipulation of the optical field, such as beam focusing, the use of ultrashort pulses, and plasmonic and near-field effects. The linear and nonlinear optical response of materials to classical optical fields as well as exploitation of the advantages of quantum lithography are discussed. 

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