Plasmon local

Rendell, R., Scalapino, D. and Miihlschlegel, B. (1978) Role of local plasmon modes in light emission from small-particle tunnel junctions. Rhys. Rev. Lett., 41, 1746-1750. 

In 1994, we proposed that a metallic needle having a nano-tip at its apex be employed as a nano-light-source for microscopy attaining nanometric spatial resolution [2]. Later, we expanded the technique to Raman spectroscopy for molecular nano-identification, nano-analysis and nano-imaging. In this chapter, we give a brief introduction to local plasmons and microscopy using a metallic nano-needle to produce the local plasmons. Then, we describe the microscope that we built and... 

Near-Field Optical Imaging of Localized Plasmon Resonances in Metal Nanoparticles... 

Imura, K. and Okamoto, H. (2008) Ultrafast photoinduced changes of eigenfunctions of localized plasmon modes in gold nanorods. Phys. Rev. B, 77, 041401(R) (4 pages). 

A large number of possible applications of arrays of nanoparticles on solid surfaces is reviewed in Refs. [23,24]. They include, for example, development of new (elect-ro)catalytical systems for applications as chemical sensors, biosensors or (bio)fuel cells, preparation of optical biosensors exploiting localized plasmonic effect or surface enhanced Raman scattering, development of single electron devices and electroluminescent structures and many other applications. 

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... 

Fig. 12.4. Suggestive set-ups for detection of mercury vapour by surface plasmon resonance (left) and localized plasmon resonance (right). The simplest configurations are shown a higher sensitivity can be obtained by using double wavelength technique [28], distributed referencing [29], bimetallic resonant mediums [26], or other approaches.

Another plasmon resonance approach for detection of mercury vapour is based on localized plasmon resonance in gold nanoparticles deposited on transparent support (Fig. 12.4, right). Changes of the refractive index of gold nanoparticles due to adsorption of mercury should lead to modification of the gold plasmon band of optical adsorption spectra. This approach has been applied successfully for investigation of interaction of biomolecules however, to our knowledge there is still no report on its applications for detection of mercury vapour. 

Localized plasmon resonance 240 Locally modified surfaces 922 Lysine 256 Lysozyme 815... 

One may be gullible to say that a small nanowire period is always desired to induce local plasmonic field enhancement, thereby strong sensitivity enhancement. What may really be critical is net nanowire or nano-groove width, i.e.,//t or ( f)A. In other words, even with a large nano wire period, one may excite LSPs efficiently if a fill factor is sufficiently small. There seems to exist a fill factor value at which local fields are maximally induced. Figure 4 presents resonance angles with and without a 1-nm thick 1,6-hexanedithiol (HOT) dielectric SAM as a VF is varied and shows enhanced plasmon momentum at ri = 50 nm and VF 0.8 and also at ri = 100 nm and VF 0.9, when nanowire gap is 10 nm in both cases [14]. In other words, absolute nanowire gap may be more important in plasmon enhancement than nanowire period. These trends have been reported in many near-held studies [15, 16]. 

Kim D (2006) Effect of resonant localized plasmon coupling on the sensitivity enhancement of nanowire-based surface plasmon resonance biosensors. J Opt Soc Am A 23 2307-2314... 

This application of STM has been introduced recently [180,181]. It uses the tip as a source of low-energy electrons which recombine in the solid. On metals, excitement of tip-induced localized plasmon modes via inelastic tunneling is the accepted mechanism for photon emission [180]. Fluorescence is also a possible mechanism [181]. A bias of 3-4 V is necessary and light is emitted in the visible range. 

Ambjomsson, T., Mukhopadhyay, Gautam,. Apell, P., Kail, M. (2006). Resonant coupling between localized plasmons and anisotropic molecular coatings in ellipsoidal metal nanoparticles. Phys. Rev. B 73 085412. 

Akiyama, T., M. Nakada, N. Terasaki, S. Yamada. (2006). Photocurrent enhancement in a porphyrin-gold nanoparticle nanostructure assisted by localized plasmon excitation. Chem. Commun. 395-397. 

Common methods for the fabrication of metallic nanoparticle arrays are electron beam lithography, photolithography, laser ablation, colloidal synthesis, electrodeposition and, in recent time, nanosphere lithography for which a monodisperse nanosphere template acts as deposition mask. A review on advances in preparation of nanomaterials with localized plasmon resonance is given in [15]. 

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