Scattering Suppression from Arbitrary Objects in Spatially-Dispersive Layered Metamaterials

Concealing objects by making them invisible to an external electromagnetic probe is coined by the term cloaking. Cloaking devices, having numerous potential applications, are still face challenges in realization, especially in the visible spectral range. In particular, inherent losses and extreme parameters of metamaterials required for the cloak implementation are the limiting factors. Here, we numerically demonstrate nearly perfect suppression of scattering from arbitrary shaped objects in spatially dispersive metamaterial acting as an alignment-free concealing cover. We consider a realization of a metamaterial as a metal-dielectric multilayer and demonstrate suppression of scattering from an arbitrary object in forward and backward directions with perfectly preserved wavefronts and less than 10% absolute intensity change, despite spatial dispersion effects present in the composite metamaterial. Beyond the usual scattering suppression applications, the proposed configuration may serve as a simple realisation of scattering-free detectors and sensors

Genetic stock characterization of fish using molecular markers

Accurate Identification of genetic resources is necessary for detecting new species and varieties for products of commercial value. Fish, as a group, apart from their economic value from a biodiversity viewpoint, have the highest species diversity among all vertebrate taxa. They exhibit enormous diversity in size, shape, biology and in the habitats they occupy. In terms of habitat diversity, fishes live in almost all conceivable aquatic habitats, ranging from Antarctic waters to desert springs. Of the 62,305 species of vertebrates recognized world over, 34,090 (nearly 52%) are valid fish species; a great majority of them (97 %) are bony fishes and the remaining (3 %) are cartilaginous (sharks and rays) and jawless fishes (lampreys and hagfishes). Further, on an average, 300 new fish species are described each year, and global surveys indicate that there could well be at least 5,000 species more to be discovered

Lateral radiative forces exerted by evanescent fields along a hyperbolic metamaterial slab

We show and investigate the optical forces acting on a particle in the vicinity of a planar waveguide which is lled with hyperbolic material and supports propagation across its plane (two-dimensional). The anisotropy axis of its medium lies in plane of the waveguide. In contrast to commonly considered pushing or pulling forces, acting in one-dimensional guiding structures, in the case of two-dimensional wave propagation, the angles between the momentum and the total energy ow may take any value around the circle. Accordingly, evanescent elds out of the slab exert lateral radiative forces on a nanoparticle oriented parallel to momentum being controllably di erent from the total energy ow direction. This provides a exibility in manipulation by nanoparticles by employing suitably engineered hyperbolic structures

Irreducible Cartesian multipole decomposition of scattered light with explicit contribution of high order toroidal moments

Multipole decomposition is a powerful tool for analysis of electromagnetic systems. This work considers high order irreducible Cartesian multipole moments in approximation of electric 32-pole and magnetic 16-pole. The explicit contributions to scattering of high order toroidal moments up to toroidal electric octupole and toroidal magnetic quadrupole are demonstrated for a dielectric high refractive index scatterer. © 2020 IOP Publishing Ltd

Purcell effect in Hyperbolic Metamaterial Resonators

The radiation dynamics of optical emitters can be manipulated by properly designed material structures providing high local density of photonic states, a phenomenon often referred to as the Purcell effect. Plasmonic nanorod metamaterials with hyperbolic dispersion of electromagnetic modes are believed to deliver a significant Purcell enhancement with both broadband and non-resonant nature. Here, we have investigated finite-size cavities formed by nanorod metamaterials and shown that the main mechanism of the Purcell effect in these hyperbolic resonators originates from the cavity hyperbolic modes, which in a microscopic description stem from the interacting cylindrical surface plasmon modes of the finite number of nanorods forming the cavity. It is found that emitters polarized perpendicular to the nanorods exhibit strong decay rate enhancement, which is predominantly influenced by the rod length. We demonstrate that this enhancement originates from Fabry-Perot modes of the metamaterial cavity. The Purcell factors, delivered by those cavity modes, reach several hundred, which is 4-5 times larger than those emerging at the epsilon near zero transition frequencies. The effect of enhancement is less pronounced for dipoles, polarized along the rods. Furthermore, it was shown that the Purcell factor delivered by Fabry-Perot modes follows the dimension parameters of the array, while the decay rate in the epsilon near-zero regime is almost insensitive to geometry. The presented analysis shows a possibility to engineer emitter properties in the structured metamaterials, addressing their microscopic structure