152 research outputs found
Egocentric physics : just about Mie
We show that the physics of anapole excitations can be accurately described
in terms of a resonant state expansion formulation of standard Mie theory
without recourse to Cartesian coordinate based `toroidal' currents that have
previously been used to describe this phenomenon. In this purely Mie theory
framework, the anapole behavior arises as a result of a Fano-type interference
effect between different quasi-normal modes of the scatterer that effectively
eliminate the scattered field in the associated multipole order.Comment: 10 pages, 5 figure
Finite frequency external cloaking with complementary bianisotropic media
We investigate the twofold functionality of a cylindrical shell consisting of
a negatively refracting heterogeneous bianisotropic (NRHB) medium deduced from
geometric transforms. The numerical simulations indicate that the shell
enhances their scattering by a perfect electric conducting (PEC) core, whereas
it considerably reduces the scattering of electromagnetic waves by closely
located dipoles when the shell surrounds a bianisotropic core. The former can
be attributed to a homeopathic effect, whereby a small PEC object scatters like
a large one as confirmed by numerics, while the latter can be attributed to
space cancelation of complementary bianisotropic media underpinning anomalous
resonances counteracting the field emitted by small objects (external
cloaking). Space cancellation is further used to cloak a NRHB finite size
object located nearby a slab of NRHB with a hole of same shape and opposite
refracting index. Such a finite frequency external cloaking is also achieved
with a NRHB cylindrical lens. Finally, we investigate an ostrich effect whereby
the scattering of NRHB slab and cylindrical lenses with simplified parameters
hide the presence of dipoles in the quasi-static limit.Comment: 16 pages, 15 figure
A review of anomalous resonance, its associated cloaking, and superlensing
We review a selected history of anomalous resonance, cloaking due to
anomalous resonance, cloaking due to complementary media, and superlensing.Comment: 15 pages and 1 figur
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