The Promise of Plasmonics

California Institute of Technology, USA.
Scientific American (Impact Factor: 1.07). 05/2007; 296(4):56-63. DOI: 10.1145/1859855.1859856
Source: PubMed

ABSTRACT Light is a wonderful medium for carrying information. Optical fibers now span the globe, guiding light signals that convey voluminous streams of voice communications and vast amounts of data. This gargantuan capacity has led some researchers to prophesy that photonic devices--which channel and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in microprocessors and other computer chips. Unfortunately, the size and performance of photonic devices are constrained by the diffraction limit; because of interference between closely spaced light waves, the width of an optical fiber carrying them must be at least half the light's wavelength inside the material. For chip-based optical signals, which will most likely employ near-infrared wavelengths of about 1,500 nanometers (billionths of a meter), the minimum width is much larger than the smallest electronic devices currently in use; some transistors in silicon integrated circuits, for instance, have features smaller than 100 nanometers.

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    • "We define one boundary of spherical shape, with 144 vertices and a diameter of 20 nm, which is shifted into the upper half space (this has no effect for a sphere embedded in a homogeneous background, but will be important for layer structures). The [2] [1] parameter indicates that the material inside the boundary is epstab{2}, and the outside material is epstab{1}. We finally indicate that the nanosphere has a closed boundary and pass the options structure op that controls the integration over boundary elements. "
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    ABSTRACT: Within the MNPBEM toolbox, developed for the simulation of plasmonic nanoparticles using a boundary element method approach, we show how to include substrate and layer structure effects. We develop the methodology for solving Maxwell's equations using scalar and vector potentials within the inhomogeneous dielectric environment of a layer structure. We show that the implementation of our approach allows for fast and efficient simulations of plasmonic nanoparticles situated on top of substrates or embedded in layer structures. The new toolbox provides a number of demo files which can also be used as templates for other simulations.
    Computer Physics Communications 12/2014; 193. DOI:10.1016/j.cpc.2015.03.023 · 3.11 Impact Factor
    • "Noble metal nanoparticles support surface plasmons, coherent oscillation of conduction band electrons, which can be excited by electromagnetic radiation to give rise to an intense electric field. Such phenomenon is called surface plasmon resonance (SPR) [5] [6]. At resonance condition, absorption of light by nanoparticles occurs which appears as absorption peaks in their absorption spectrum. "
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    ABSTRACT: Solid supported 2D assembly of silver nanocubes was fabricated by Langmuir-Blodgett technique and employed to investigate its surface enhanced Raman scattering (SERS) and surface enhance fluorescence (SEF) activities by detecting Rh6G in solution of varied concentrations, that is, 10 −12 M, 10 −9 M, 10 −6 M, and 10 −3 M. SERS was detected from a nanomolar concentration of Rh6G whereas SEF was detected from a picomolar concentration. Further, the substrate was subjected to thermal annealing to fabricate plasmonic thin film. The formation of thin film was followed by monitoring its surface plasmon resonance spectra and atomic force microscopic images. It was observed that the characteristic spectral peaks of silver nanocubes merged into a broad spectral band as the annealing time was increased and the intensity of the band decreased with the formation of thin film. The obtained result implies that thermal annealing could be a simple approach to create nanoscale gaps in SERS substrate and to engineer continuous thin film from the assembly of discrete nanoparticles.
    01/2014; 2014(12):1-9. DOI:10.1155/2014/602385
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    • "In the past decade, there have been many breakthroughs in the field of plasmonics and metamaterials that have enabled optical devices with unprecedented functionalities [1] [2] [3] [4]. Many of these devices have remained in research laboratories without being realized in commercial production lines because of many technological hurdles. "
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    ABSTRACT: Searching for better materials for plasmonic and metamaterial applications is an inverse design problem where theoretical studies are necessary. Using basic models of impurity doping in semiconductors, transparent conducting oxides (TCOs) are identified as low-loss plasmonic materials in the near-infrared wavelength range. A more sophisticated theoretical study would help not only to improve the properties of TCOs but also to design further lower-loss materials. In this study, optical functions of one such TCO, gallium-doped zinc oxide (GZO), are studied both experimentally and by first-principles density-functional calculations. Pulsed-laser-deposited GZO films are studied by the x-ray diffraction and generalized spectroscopic ellipsometry. Theoretical studies are performed by the total-energy-minimization method for the equilibrium atomic structure of GZO and random phase approximation with the quasiparticle gap correction. Plasma excitation effects are also included for optical functions. This study identifies mechanisms other than doping, such as alloying effects, that significantly influence the optical properties of GZO films. It also indicates that ultraheavy Ga doping of ZnO results in a new alloy material, rather than just degenerately doped ZnO. This work is the first step to achieve a fundamental understanding of the connection between material, structural, and optical properties of highly doped TCOs to tailor those materials for various plasmonic applications.
    Physical Review X 11/2013; 3(4). DOI:10.1103/PhysRevX.3.041037 · 9.04 Impact Factor
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