Asymmetric backscattering from the hybrid magneto-electric meta particle

Kozlov, Vitali; Filonov, Dmitry; Shalin, Alexander S.; Steinberg, Ben Z.; Ginzburg, Pavel

doi:10.1063/1.4967238

Cited by 47 publications

(30 citation statements)

References 35 publications

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“…In order to demonstrate this effect, a scatterer, which electromagnetic analysis requires at least two leading dipole terms in the multipolar decomposition will be considered. While two dissimilar electric dipoles, separated by a wavelengthcomparable distance could possess asymmetric back scattering, being illuminated from opposite sides, combination of electric and magnetic dipoles was recently shown to provide an ultimate degree of asymmetry [10]. The hybrid magneto-electric particle (HMEP) consists of a SRR and a thin wire ( Fig.…”

Section: Theoretical Formulationmentioning

confidence: 99%

“…In principle, a HMEP made of a pair of isotropic ED and MD, will show a similar micro-Doppler behavior to the one discussed hereafter. Adiabatic theory is based on the matrix formulation [10] and polarizability tensors, taken from Eq. 1.…”

Section: Adiabatic Theorymentioning

confidence: 99%

“…In particular, micro-Doppler frequency comb generation from a hybrid magneto-electric particle (HMEP), consisting of a split ring resonator (SRR) and a thin wire is studied. The HMEP has asymmetric backscattering when illuminated by a plane wave from opposite directions [10] and, as the result, it shows completely different micro-Doppler combs, detected at forward and backward directions ( Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Asymmetric micro-Doppler frequency comb generation via magnetoelectric coupling

2017

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Abstract:Electromagnetic scattering from moving bodies, being inherently time-dependent phenomenon, gives rise to a generation of new frequencies, which could characterize the motion. While a standard linear path leads to a constant Doppler shift, accelerating scatterers could generate a micro-Doppler frequency comb. Here, a spectra produced by rotating objects, was studied and observed in a bi-static 'lock in' detection scheme. Internal geometry of a scatterer was shown to determine the spectra, while the degree of structural asymmetry was suggested to be identified via signatures in the micro-Doppler comb. In particular, hybrid magneto-electric particles, showing an ultimate degree of asymmetry in forward and backward scattering directions were investigated. It was shown that the comb in the backward direction has signatures at the fundamental rotation frequency and its odd harmonics, while in the forward scattered field has the prevailing peak at the doubled frequency and its multiples. Additional features in the comb were shown to be affected by the dimensions of the particle and strength of magneto-electric coupling. Experimental verification was performed with a printed circuit board antenna, based on a wire and a split ring, while the structure was illuminated with at 2GHz carrier frequency. Detailed analysis of micro-Doppler combs enables remote detection of asymmetric features of distant objects and could find use in a span of applications, including stellar radiometry and radio identification.

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Section: Theoretical Formulationmentioning

confidence: 99%

Section: Adiabatic Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Asymmetric micro-Doppler frequency comb generation via magnetoelectric coupling

2017

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“…Individual and arrayed bianisotropic metamolecules have been designed and fabricated using a variety of material platforms, both dielectric and metallic, across a wide spectral range, from centimeters to nanometers [ 4,28,29,30,31,32,33,34,35]. While the interference between in-plane electric and magnetic resonances excited by a normally incident electromagnetic wave can introduce the up-down (forward/backward) scattering asymmetry, it has recently been shown that bianisotropic coupling between in-plane electric and out-of-plane magnetic moments can induce strong lateral scattering asymmetry [ 28,36] by a single metamolecule.…”

Section: Introductionmentioning

confidence: 99%

Perfect Diffraction with Multiresonant Bianisotropic Metagratings

et al. 2018

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One highly desirable function of a diffraction grating is its ability to deflect incident light into a specific diffraction order with near-perfect efficiency. While such asymmetry can be achieved in a variety of ways, e.g., by using a sawtooth (blazed) geometry, a recently emerged approach is to use a planar metagrating comprised of designer multi-resonant periodic units (metamolecules). Here we demonstrate that a bianisotropic unit cell supporting four resonances interfering in the far field can be used as a building block for achieving the prefect deflection. A coupled mode analysis shows that these modes provide a small number of orthogonal electromagnetic radiation patterns that are needed to suppress transmission/reflection into all but one diffraction order. Bianisotropy caused by a mirror symmetry breaking enables a normally incident wave to excite, through near-field couplings, two otherwise "dark" resonant modes. We design and experimentally realize bianisotropic metamolecules which are sub-wavelength in all three dimensions, and whose optical properties are desensitized to fabrication imperfections by their geometric simplicity. We show that optical beams tightly focused onto the metagratings with just a few unit cells can also be asymmetrically deflected with high efficiency, paving the way for compact broadband optical devices.

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“…Except for a certain interest for mathematical physics, the analytical solutions may serve for description of structural anisotropy of metamaterials (see recent Refs. [37,38]), caused by the anisotropy of individual meta-atoms but not the lattice. In this case, the multipolar moments of these meta-atoms determine the properties of the whole metamaterial.…”

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confidence: 99%