Time-varying metamaterials are currently at the forefront of research, offering immense possibilities for intriguing wave manipulations. Temporal modulations have paved way unconventional realizations magnetless nonreciprocity, amplification, frequency conversion, pulse shaping, and much more. Here, we overview fundamentals recent advancements temporal interfaces in isotropic, anisotropic, bianisotropic materials metamaterials. Delving into scattering media different material classes, draw...

Abstract Multipoles are paramount for describing electromagnetic fields in many areas of nanoscale optics, playing an essential role the design devices plasmonics and all‐dielectric nanophotonics. Challenging traditional division into electric magnetic moments, toroidal moments proposed as a physically distinct family multipoles with significant contributions to properties matter. However, apparent impossibility separately measuring their response sheds doubt on true physical significance....

Efficient trapping of light in nanostructures is essential for the development optical devices based on interaction between and matter. In this work, we show theoretically experimentally that one-dimensional arrays subwavelength dielectric Mie-resonant particles can support collective resonances with increased Q-factors. We demonstrate increase Q-factor be explained by electric magnetic dipole modes chain resulting appearance inflection point at band edge. The considered effect studied...

Periodicity is usually assumed to be the necessary and sufficient condition for formation of band gaps, i.e., energy bands with a suppressed density states. Here, we check this premise by analyzing gap properties three structures that differ in degree periodicity ordering. We consider photonic crystal, disordered lattice, ordered but nonperiodic quasicrystalline structure. A real-space metric allows us compare these different structures. Using metric, reveal lattice quasicrystal can...

The article considers ways to preserve populations of protected plant species on the example a natural regional wood park "Sludah woods" in Nizhny Novgorod. population fitness is assessed, including environmental conditions, density and ontogenetic percentage. conditions according Ellenberg scores are assessed. conservation repatriation considered. Recommendations supposed use agrotechnical measures conserve rare herbaceous under urban environment.

We present a system to create Mobile Realistic Fullbody (MoRF) avatars. MoRF avatars are rendered in real-time on mobile devices, learned from monocular videos, and have high realism. use SMPL-X as proxy geometry render it with DNR (neural texture image-2-image network). improve prior work, by overfitting perframe warping fields the neural space, allowing better align training signal between different frames. also refine mesh fitting procedure overall avatar quality. In comparisons other...

An exact solution of the homogeneous wave equation, which was found previously, is treated from point view continuous wavelet analysis (CWA). If time a fixed parameter, represents new multidimensional mother for CWA. Both and its Fourier transform are given by explicit formulae exponentially localized. The directional. widths uncertainty relation investigated numerically. certain parameter large, behaves asymptotically as Morlet wavelet. physical in definition Kaiser, it may be interpreted...

An experimental demonstration of directivities exceeding the fundamental Kildal limit, a phenomenon called superdirectivity, is provided for spherical high-index dielectric antennas with an electric dipole excitation. A directivity factor about 10 total efficiency more than 80% antenna having size third wavelength was measured. High are shown to be associated constructive interference particular and magnetic modes open resonator. Both analytic solutions point full-wave rigorous simulation...

Design methods in the reciprocal space allow one to obtain structures with desired properties. Quasicrystalline photonic structures, which ensure selective scattering of an electromagnetic wave incident on sample, have been designed. The maxima Fourier transform distribution permittivity are located along two arcs Ewald sphere, corresponds required wavelength and angle incidence. material has determined by transition real space. A structure a low dielectric contrast formed after binarization...

An integral representation of solutions the wave equation as a superposition other this is built. The from wide class can be used building blocks for representation. Considerations are based on mathematical techniques continuous wavelet analysis. formulas obtained justified point view distribution theory. A comparison results with those by G. Kaiser carried out. Methods obtaining physical wavelets discussed.

Abstract Reciprocal space engineering allows tailoring the scattering response of media with a low refractive‐index contrast. Here it is shown that quasiperiodic leveled‐wave structure well‐defined reciprocal and random real distribution can be engineered to open complete photonic bandgap (CPBG) for any For these structures, an analytical estimation derived, which predicts there optimal number Bragg peaks A finite 2D or 3D CPBG expected at this even arbitrarily small Results numerical...

Abstract Since the initial discovery of Dyakonov surface waves at a flat infinite interface two dielectrics, least one which is positively anisotropic , extensive research has been conducted towards their theoretical and experimental studies in materials with positive anisotropy. The potential applications these were initially limited due to stringent conditions for existence requirement position In our study, we present prediction observation novel type that propagate along strip between...

The new approach to the wavelet analysis for solutions of homogeneous wave equation in three spatial dimensions is presented. based on ideas suggested by G. Kaiser but has different implementation and some advantages versus known approach. A physical this also presented, with brief discussion its main properties. become widely used during last twenty years it a lot applications nowadays. However most them are field numerical processing experimental data, digital images, astronomical,...

Being a general wave phenomenon, bound states in the continuum (BICs) appear acoustic, hydrodynamic, and photonic systems of various dimensionalities. Here, we report first experimental observation an accidental electromagnetic BIC one-dimensional periodic chain coaxial ceramic disks. We show that manifests itself as narrow peak transmission spectra placed between two loop antennas. demonstrate linear growth radiative quality factor BICs with number disks is well-described tight-binding...

In this work, we investigate the possibilities of reaching wide-angle perfect absorption with Huygens' metasurfaces possessing both electric and magnetic responses. We analyze role anisotropy polarizability tensor unit cell reveal conditions for optimal angular stability in symmetric as well polarization independence. Then approximate desirable behavior a metasurface whose reflectance is low wide frequency range while total around single resonance frequency. Reaching was numerically...

A simple analytical explanation of the directed diffraction phenomenon is presented. This shown to be associated with hyperbolic points a dispersive surface. The simplest one-dimensional model photonic crystal taken demonstrate theory. correspond lower boundaries band gaps. was observed both analytically and numerically by using FDTD simulation.

A mathematical model is presented and characteristic transient processes in synchronous motors of variable frequency drives associated with load acceptance shedding, changes power supply voltage speed adjusting are considered. The results can be useful studying the features drive adjustment as well formation requirements for reconstruction gas compressor units at stations pump oil pumping main pipelines.

We consider a one-dimensional photonic crystal consisting of alternating dielectric layers two types. The dispersion relation for such gives the dependence frequency on transverse wave vector and quasi-momentum. If incident coincides with saddle point, behavior envelope field is determined by hyperbolic equation, where longitudinal coordinate plays role time. Depending parameters isofrequency contour, canalization or localization may occur. correspond to localization, it can be achieved...

An asymptotic investigation of monochromatic electromagnetic fields in a layered periodic medium is carried out under the assumption that wave frequency close to stationary point dispersion surface. We find solutions Maxwell equations by method two-scale expansions. establish principal order expansion solution dependent on three spatial coordinates sum two differently polarized Floquet-Bloch solutions, each which multiplied slowly varying envelope function. derive functions satisfy system...

A bandgap in the continuum spectrum of photons addition to its basic physical significance has strong potential for applications. Analogous semiconductor crystals electrons, periodic dielectric structures named photonic were proposed control photon flux propagation. In our search low refractive index (RI) with a bandgap, initial research efforts focused on crystal design, while aperiodic allow lower values contrast sustain bandgap. Here, we report two-dimensional quasicrystalline structure...