arXiv subjects

Kseniia Baryshnikova

Publications and source records attributed to Kseniia Baryshnikova.

9 recordsLinked to original sources

arXiv2022

Multipolar theory of bianisotropic response

Bianisotropy of metaatoms is usually associated with their nonlocal response and the mutual coupling between electric and magnetic dipole moments induced by the incident field. In this work, we generalize the theory of bianisotropy beyond the dipole response to the cases of arbitrary high-order multipole resonances. We demonstrate that bianisotropy is exclusively caused by the absence of the inversion symmetry of metaatoms. The strength of the bianisotropy response is normally increased with the size of a meta-atom but its origin is fully connected to the symmetry of the structure. As an important example of bianisotropic particle, we consider a triangular prism and show how accounting for the higher-order multipoles prevents the violation of the Onsager-Casimir conditions for kinetic coefficients appearing in the dipole approximation. The developed theory is an important step towards a deeper insight into the scattering properties of nanoantennas and meta-atoms.

physics.optics↗

arXiv2021

Polarization switching of quasi-trapped modes and near field enhancement in bianisotropic all-dielectric metasurfaces

A general strategy for the realization of electric and magnetic quasi-trapped modes located at the same spectral position is presented. This strategy's application makes it possible to design metasurfaces allowing switching between the electric and magnetic quasi-trapped modes by changing the polarization of the incident light wave. The developed strategy is based on two stages: the application of the dipole approximation for determining the conditions required for the implementation of trapped modes and the creation of the energy channels for their excitation by introducing a weak bianisotropy in nanoparticles. Since excitation of trapped modes results in a concentration of electric and magnetic energies in the metasurface plane, the polarization switching provides possibilities to change and control the localization and distribution of optical energy at the sub-wavelength scale. We demonstrate a practical method for spectral tuning of quasi-trapped modes in metasurfaces composed of nanoparticles with a pre-selected shape. As an example, the optical properties of a metasurface composed of silicon triangular prisms are analyzed and discussed.

physics.optics↗

arXiv2020

Broadband antireflection with halide-perovskite metasurfaces

Meta-optics based on optically-resonant dielectric nanostructures is a rapidly developing research field with many potential applications. Halide perovskite metasurfaces emerged recently as a novel platform for meta-optics, and they offer unique opportunities for control of light in optoelectronic devices. Here we employ the generalized Kerker conditions to overlap electric and magnetic Mie resonances in each meta-atom of MAPbBr3 perovskite metasurface and demonstrate broadband suppression of reflection down to 4%. We reveal also that metasurface nanostructuring is also beneficial for the enhancement of photoluminescence. Our results may be useful for applications of nanostructured halide perovskites in photovoltaics and semi-transparent multifunctional metadevices where reflection reduction is important for their high efficiency.

physics.optics↗

arXiv2019

Strong asymmetry of forward scattering effect from dielectric cubic nanoantenna in lossless media

Dielectric photonics platform provides unique possibilities to control light scattering via utilizing high-index dielectric nanoantennas with peculiar optical signatures. Despite the intensively growing field of all-dielectric nanophotonics, it is still unclear how surrounding media affect scattering properties of a nanoantenna with complex multipole response. Here we report on light scattering by a silicon cubic nanoparticles embedded in lossless media, supporting optical resonant response. We show that significant changes in the scattering process are governed by the electro-magnetic multipole resonances which experience spectral red-shift and broadening over the whole visible and near-infrared spectra as the indices of media increase. Most interestingly that the considered nanoantenna exhibits the broadband forward scattering in the visible and near-infrared spectral ranges due to the Kerker-effect in high-index media. The revealed effect of broadband forward scattering is essential for highly demanding applications in which the influence of the media is crucial such as health-care: sensing, treatment efficiency monitoring, and diagnostics. In addition, the insights from this study are expected to pave the way towards engineering the nanophotonic systems including but not limited to Huygens-metasurfaces in media within a single framework.

physics.optics↗

arXiv2018

Smart Table Based on Metasurface for Wireless Power Transfer

Metasurfaces have been investigated and its numerous exotic functionalities and the potentials to arbitrarily control of the electromagnetic fields have been extensively explored. However, only limited types of metasurface have finally entered into real products. Here, we introduce a concept of a metasurface-based smart table for wirelessly charging portable devices and report its first prototype. The proposed metasurface can efficiently transform evanescent fields into propagating waves which significantly improves the near field coupling to charge a receiving device arbitrarily placed on its surface wirelessly through magnetic resonance coupling. In this way, power transfer efficiency of 80$\%$ is experimentally obtained when the receiver is placed at any distances from the transmitter. The proposed concept enables a variety of important applications in the fields of consumer electronics, electric automobiles, implanted medical devices, etc. The further developed metasurface-based smart table may serve as an ultimate 2-dimensional platform and support charging multiple receivers.

physics.app-ph↗

arXiv2018

Optical anapoles in nanophotonics and meta-optics

Interference of electromagnetic modes supported by subwavelength photonic structures is one of the key concepts that underpins the subwavelength control of light in meta-optics. It drives the whole realm of all-dielectric Mie-resonant nanophotonics with many applications for low-loss nanoscale optical antennas, metasurfaces, and metadevices. Specifically, interference of the electric and toroidal dipole moments results in a very peculiar, low-radiating optical state associated with the concept of optical anapole. Here, we uncover the physics of multimode interferences and multipolar interplay in nanostructures with an intriguing example of the optical anapole. We review the recently emerged field of anapole electrodynamics explicating its relevance to multipolar nanophotonics, including direct experimental observations, manifestations in nonlinear optics, and rapidly expanding applications in nanoantennas, active photonics, and metamaterials.

physics.optics↗

arXiv2017

Giant magneto-electric field separation via near-field interference on anapole-like states

Quality of spatial separation between electric and magnetic fields in an electromagnetic wave is fundamentally constrained by nonlocal nature of Maxwell equations. While electric and magnetic energy densities in a wave, propagating in vacuum, are equal at each point in space, carefully designed photonic structures can enable surpassing this limit. Here, a set of high index dielectric tubes was for the first time proposed and theoretically and experimentally demonstrated to deliver a record high spatial separation, overcoming the free space scenario by more than three orders of magnitude with simultaneous enhancement of the magnetic field. Separation effect in the proposed structure is enabled by the near-field interference on anapole-like states, designed by tuning geometrical parameters of coupled dielectric tubes. The void layout of the structure enables the direct observation of the effect with near-field probes and could be further employed for relevant applications. Novel devices, providing tunable high quality separation between electric and magnetic fields, are extremely important for metrology, spectroscopy, spintronics, and opto-electronic applications.

physics.optics↗

arXiv2017

Reflection compensation mediated by electric and magnetic resonances of all-dielectric metasurfaces

All-dielectric nanostructures have recently emerged as a promising alternative to plasmonic devices, as they also possess pronounced electric and magnetic resonances and allow effective light manipulation. In this work, we study optical properties of a composite structure that consists of a silicon nanoparticle array (metasurface) and high-index substrate aiming at clarifying the role of substrate on reflective properties of the nanoparticles. We develop a simple semi-analytical model that describes interference of separate contributions from nanoparticle array and the bare substrate to the total reflection. Applying this model, we show that matching the magnitudes and setting the π-phase difference of the electric and magnetic dipole moments induced in nanoparticles, one can obtain a suppression of reflection from the substrate coated with metasurface. We perform numerical simulations of sphere and disk nanoparticle arrays for different permittivities of the substrate. We find full agreement with the semi-analytical results, which means that the uncoupled-element model adequately describes nanostructure reflective properties, despite the effects of induced bi-anisotropy. The model explains the features of the reflectance spectrum, such as a number of dips and their spectral positions, and show why it may not coincide with the spectral positions of Mie resonances of the single nanoparticles forming the system. We also address practical aspects of the antireflective device engineering: we show that the uncoupled-element model is applicable to the structures on top of silicon substrates, including lithographically defined nanopillars. The reflectance suppression from nanoparticle array on top of the silicon substrate can be achieved in a broad spectral range with disordered nanoparticle array and for a wide range of incidence angles.

physics.optics↗

arXiv2015

Enhancement of artificial magnetism via resonant bianisotropy

All-dielectric "magnetic light" nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here a new approach for increasing magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer nanoantenna. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of magnetic polarizability, tailoring the later in the dynamical range of 100 % and enhancement up to 36 % relative to performances of standalone spherical particles. The proposed approach provides pathways for designs of all-dielectric metamaterials and metasurfaces with strong magnetic response.

physics.optics↗