Article

Self-Similar Chain of Metal Nanospheres as an Efficient Nanolens

Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia, United States
Physical Review Letters (Impact Factor: 7.51). 12/2003; 91(22):227402. DOI: 10.1103/PhysRevLett.91.227402
Source: PubMed

ABSTRACT

As an efficient nanolens, we propose a self-similar linear chain of several metal nanospheres with progressively decreasing sizes and separations. To describe such systems, we develop the multipole spectral expansion method. Optically excited, such a nanolens develops the nanofocus ("hottest spot") in the gap between the smallest nanospheres, where the local fields are enhanced by orders of magnitude due to the multiplicative, cascade effect of its geometry and high Q factor of the surface plasmon resonance. The spectral maximum of the enhancement is in the near-ultraviolet region, shifting toward the red region as the separation between the spheres decreases. The proposed system can be used for nanooptical detection, Raman characterization, nonlinear spectroscopy, nanomanipulation of single molecules or nanoparticles, and other applications.

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    • "Among various metal nanoparticles, gold nanoparticles are multifunctional inorganic metal which has application in different fields such as nano-enginering (Li et al., 2003), nano-electronics (Barnes et al., 2003), biosensors (Elghanian et al., 1997), biological imaging (Jain et al., 2006) and other technologies. Even, it exhibits excellent anti-bacterial properties (Zhao et al., 2010; Demurtas and Perry, 2014). "
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    • "Among various metal nanoparticles, gold nanoparticles are multifunctional inorganic metal which has application in different fields such as nano-enginering (Li et al., 2003), nano-electronics (Barnes et al., 2003), biosensors (Elghanian et al., 1997), biological imaging (Jain et al., 2006) and other technologies. Even, it exhibits excellent anti-bacterial properties (Zhao et al., 2010; Demurtas and Perry, 2014). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Gold (Au)–Polycarbonate (PC) matrix was prepared by gamma radiation assisted diffusion of Au nanoparticles in PC matrix. UV–Visible spectroscopy showed the surface plasmon resonance around 550 nm which corresponds to Au and this peak shift towards lower wavelength i.e. blue shift indicating the decrease in particle size of Au. Rutherford Backscattering (RBS) experiment confirmed the diffusion of Au in PC and depth of diffusion is found to be around 0.85 µm. X-ray Diffractogram (XRD) results also revealed the diffusion of Au in PC where the peak observed at 2θ∼38.29° which correspond to the FCC structure. Scanning Electron Microscope (SEM) images showed the hexagonal shaped Au nanoparticles and average particle size is found to be around 110 nm. These samples also showed anti-bacterial properties with both gram positive and gram negative bacteria's and revealed the inhibition of the overall growth of the bacteria with gamma dose.
    Full-text · Article · Mar 2015 · Radiation Physics and Chemistry
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