arXiv subjects

Mikhail Sidorenko

Publications and source records attributed to Mikhail Sidorenko.

7 recordsLinked to original sources

arXiv2026

Towards compact high-frequency nonreciprocal devices using nanoplasma-switched time-varying metasurfaces

Time-modulated systems have received growing interest in recent years. They allow us to tailor effects, such as frequency conversion, single-direction propagation, etc. For the microwave band, semiconductor elements, such as varactors, are usually used as time-modulated elements but their modulation frequency has been limited to the few-gigahertz range. Recent advances in nanoplasma switches, i.e., two-state electronic switches based on a gas discharge in a nanometer-scale gap, provide a new potential for developing time-modulated systems with high operating frequencies. Here, we develop an analytical framework based on the time-Floquet method for the design of nonreciprocal time-modulated devices based on two-state time-modulated elements, for instance, nanoplasma-based switches. A practical example of a microwave isolator operating at 100~GHz frequency is developed and studied both analytically and using full-wave simulations. A potential realization in a parallel-plate waveguide is also simulated numerically.

physics.optics↗

arXiv2025

Bound states in the continuum in a chain of coupled Mie resonators with structural disorder: theory and experiment

We study the impact of structural disorder on a radiative lifetime of symmetry-protected bound state in the continuum (BIC) and a bright mode in a one-dimensional periodic chain of coupled Mie resonators. Through experimental, simulation, and theoretical approach, we reveal an unusual linear decay in the radiative quality factor of the BIC with the increase of the disorder amplitude, contrasting with the quadratic decay observed in recent studies. We also investigate modes with different symmetries and show that the behavior of the quality factor in a strongly disordered system depends on the mode's multipolar origin. Our findings are pivotal for the practical application of BICs, particularly in natural and self-assembled photonic structures where structural disorder plays a crucial role.

physics.optics↗

arXiv2024

Time Interfaces in Nanoplasma-Switched Wire Media

In this work, we consider instantaneous transitions of an infinitely extended uniaxial dielectric into a wire medium (WM) of continuous infinitely long conducting wires. Due to the strong spatial dispersion in the WM the known (Morgenthaler's) theory of temporal discontinuities is not applicable. We solve this problem analytically in time domain. We show that a transverse electromagnetic (TM) plane wave transforms into four waves: a pair of TM waves and a pair of transverse electromagnetic waves. This way, the power flow splits into two different directions, with one of them along the wires. Such a transition can possibly be achieved by nanoplasma discharges in the gaps of the split wires, initiated by an external voltage source applied to the wire and transforming the split wires forming the uniaxial dielectric into continuous ones.

physics.optics↗

arXiv2024

Long-Range Over-a-Meter NFC Antenna Design and Impedance Matching

NFC and RFID technologies have seen significant advancements, with expanding applications necessitating the design of novel antenna structures that enhance range capabilities. This paper presents a study on the design and impedance matching of long-range NFC coils, focusing on optimizing antenna performance over distances exceeding one meter. Through numerical analyses of various coil geometries, including single-turn and multi-wire configurations, we explore the effects of coil size, wire separation, and current distribution on magnetic field generation. Additionally, an adaptive impedance matching approach is proposed to maintain efficient power transfer, significantly improving field strength and system performance. The proposed designs demonstrate superior interrogation distances compared to existing configurations, highlighting the potential for enhanced long-range NFC applications.

physics.app-ph↗

arXiv2023

Engineering of high-$Q$ states via collective mode coupling in chains of Mie resonators

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

physics.optics↗

arXiv2023

MoRF: Mobile Realistic Fullbody Avatars from a Monocular Video

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. We use SMPL-X as a proxy geometry and render it with DNR (neural texture and image-2-image network). We improve on prior work, by overfitting per-frame warping fields in the neural texture space, allowing to better align the training signal between different frames. We also refine SMPL-X mesh fitting procedure to improve the overall avatar quality. In the comparisons to other monocular video-based avatar systems, MoRF avatars achieve higher image sharpness and temporal consistency. Participants of our user study also preferred avatars generated by MoRF.

cs.CV↗

arXiv2022

On the existence of pure, broadband toroidal sources in electrodynamics

Multipoles are paramount for describing electromagnetic fields in many areas of nanoscale optics, playing an essential role for the design of devices in plasmonics and all-dielectric nanophotonics. Challenging the traditional division into electric and magnetic moments, toroidal moments have been proposed as a physically distinct family of multipoles with significant contributions to the properties of matter. However, the apparent impossibility of separately measuring their response sheds doubt on their true physical significance. Here, we confirm the possibility of selectively exciting toroidal moments without any other multipole. We develop a set of general conditions that any current distribution must fulfill to be entirely described by toroidal moments, and prove our results in an analytically solvable case. Our new theory allows us to design and verify experimentally for the first time an artificial structure supporting a pure, broadband toroidal dipole response in the complete absence of the electric dipole and other 'ordinary' multipole contributions. In addition, we propose a structure capable of supporting a novel type of nonradiating source, a 'toroidal anapole', originating from the destructive interference of the toroidal dipole with the unconventional electromagnetic sources known as mean square radii. The results in this work provide conclusive evidence on the independent excitation of toroidal moments in electrodynamics.

physics.class-ph↗