Superscattering of Light from Subwavelength Nanostructures

Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
Physical Review Letters (Impact Factor: 7.51). 07/2010; 105(1):013901. DOI: 10.1103/PhysRevLett.105.013901
Source: PubMed


We provide a theoretical discussion of the scattering cross section of individual subwavelength structures. We show that, in principle, an arbitrarily large total cross section can be achieved, provided that one maximizes contributions from a sufficiently large number of channels. As a numerical demonstration, we present a subwavelength nanorod with a plasmonic-dielectric-plasmonic layer structure, where the scattering cross section far exceeds the single-channel limit, even in the presence of loss.

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Available from: Zhichao Ruan, Jul 28, 2015
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    • "Eq. (1) enables us to navigate between the two systems and relate their material parameters in a unique, systematic and rigorous way. Pendry et al. [1], Schurig et al. [15], and a number of other workers [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [16] [17] [18] have leveraged the fact that the medium parameters can be related via (1), in order to lay the foundations of designing cloaks, which render a target invisible when covered by using materials whose parameters are dictated by the TO. We will now explain the basic principles of TO-based cloaking, which, in principle, can render an object totally invisible . "
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    ABSTRACT: In this paper we present an alternative approach to addressing the problem of designing cloaks for radar targets, which have been dealt with in the past by using the transformation optics (TO) algorithm. The present design utilizes realistic materials, which can be fabricated in the laboratory, and are wideband as well as relatively insensitive to polarization and incident angle of the incoming wave. The design strategy, presented herein, circumvents the need to use metamaterials for cloak designs that are inherently narrowband, dispersive and highly sensitive to polarization and incident angle. A new interpretation of the TO algorithm is presented and is employed for the design of radar cross section-reducing absorbers for arbitrary targets, and not just for canonical shapes, e.g., cylinders. The topic of performance enhancement of the absorbers by using graphene materials and embedded frequency structure surfaces is briefly mentioned. The design procedure for planar absorbing covers is presented and their performance as wrappers of general objects is discussed. A number of test cases are included as examples to illustrate the application of the proposed design methodology, which is a modification of the classical TO paradigm.
    06/2013; 13(2). DOI:10.5515/JKIEES.2013.13.2.73
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    • "Despite its long history, the research on EM scattering still reveals surprises. Giant resonances that anomalously increase with the resonance order (dipole, quadrupole, etc) [3], the formation of complex field structures with vortices inside scattering particles [4], and the superscattering of light in subwavelength structures, in which the single-channel limit can be overcome [5], are some examples of interesting, unexpected, and basic phenomena that have been recently unveiled in the field of EM scattering. Most of these recent results have been driven by the extraordinary technological progress in the emerging field of nanophotonics. "
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    Journal of optics 05/2012; DOI:10.1088/2040-8978/14/6/065101 · 2.06 Impact Factor
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    ABSTRACT: The influence of the spherical anisotropy (SA) of a middle layer on the plasmon resonance couplings in the sandwiched gold nanoshell (Au/SA/Au) has been investigated by means of a modified Mie theory. It is found that the plasmon couplings in the Au/SA/Au nanoshells are more sensitive to the permittivity along the radial direction of SA layer than the permittivity along the tangential direction. With increasing the anisotropic value of the middle layer, the dipole peaks of antisymmetric ω −− mode and symmetric ω −+ mode both show blue-shifts, while the shift of the antisymmetric ω −− mode is larger than that for the symmetric ω −+ mode. The larger anisotropic value of the SA layer induces the stronger near-field outside the nanoparticles for the antisymmetric ω −− mode, while the smaller anisotropic value makes the larger near-field for the symmetric ω −+ mode. We further have found that the middle SA layer with smaller anisotropic value is helpful to obtain larger electric fields inside the nanoshells, which may be useful for their potential applications in nonlinear optics.
    12/2012; 45(4). DOI:10.1007/s13404-012-0068-3
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