Pavel A. Belov

ITMO University | SPbNRU ITMO

We show that a slab of wire medium composed of thin parallel metallic wires can naturally support bound states in the continuum (BICs) formed in an unusual way. The revealed BICs appear due to the strong spatial dispersion making possible the propagation of longitudinal plasma-like waves and TEM polarized modes with a flat band. The symmetry-protec...

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 of about 10 with a total efficiency of more than 80% for an antenna having a size of a third of the wavelength...

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 of about 10 with a total efficiency of more than 80% for an antenna having a size of a third of the wavelength...

Electrically small dielectric antennas are of great interest for modern technologies, since they can significantly reduce the physical size of electronic devices for processing and transmitting information. We investigate the influence of the resonance conditions of an electrically small dielectric spherical antenna with a high refractive index on...

In this work, we consider the optical properties of icosahedral quasicrystals. Quasicrystals were created by direct laser writing. This method of creation made it possible to create three-dimensional structures of high quality. Optical properties were investigated using optical diffraction. The diffraction patterns from such structures were experim...

One of the most intriguing problems of light transport in solids is the localization that has been observed in various disordered photonic structures. The light localization in defect‐free icosahedral quasicrystals has recently been predicted theoretically without experimental verification. Herein, the fabrication of submicron‐size dielectric icosa...

In this paper we address the possibility to perform imaging of two samples within the same acquisition time using coupled ceramic resonators and one transmit/receive channel. We theoretically and experimentally compare the operation of our ceramic dual‐resonator probe with a wire‐wound solenoid probe, which is the standard probe used in ultrahigh‐f...

The modern development of wireless power transfer (WPT) technologies brings various products that improve the lives of users. It has become an urgent demand to simultaneously charge multiple mobile devices operating under different WPT standards on a charging platform regardless of their position and orientation with respect to each other. Recent a...

The metasurface-based concept of a smart table for wireless power transfer (WPT) has been recently proposed and experimentally proven to be capable of transferring energy to 1 meter with high efficiency. However, in reality, we usually encounter the need to transfer energy to several receivers and with the presence of various obstacles. Herein, we...

Currently, human magnetic resonance (MR) examinations are becoming highly specialized with a pre-defined and often relatively small target in the body. Conventionally, clinical MR equipment is designed to be universal that compromises its efficiency for small targets. Here, we present a concept for targeted clinical magnetic resonance imaging (MRI)...

High refractive index (HRI, n>1.8) photonic structures offer strong light confinement and refractive efficiencies, cover the entire visible spectrum and can be tuned by designing geometric arrayed features. However, its practical applications are still hindered by the applicability and material limitation of lithography-based micro/nano fabrication...

Radio-frequency (rf) coils are used in all clinical and research magnetic-resonance-imaging (MRI) systems to excite nuclear spins and to receive signals from them. The quality of imaging depends strongly on the signal-to-noise ratio (SNR) and the transmit efficiency of the coils. The birdcage volume coils used in most MRI scanners for homogeneous i...

Magnetic Resonance Imaging (MRI) is an imaging technique exploiting the magnetic resonance of specific nuclear spins, like protons. In this paper, MR probes based on dielectric ring resonators are investigated from a theoretical approach. We take advantage of the high-permittivity and low-losses properties of the ceramic material used for manufactu...

A metamaterial-inspired resonator for free-positioning wireless charging of several devices is proposed and numerically studied. The resonator is based on orthogonal metallic wires arrays deposited on a high permittivity low loss dielectric substrate. Given a fixed area of 50 × 50 cm, its resonant frequency can be tuned in a wide frequency band fro...

The ability of all-dielectric nanostructures to perform exotic photonics effects is with superior efficiency compared to their metallic counterparts. Free from joules losses, high-index dielectrics support comparable excitation of electric and magnetic resonances and pave a way to advanced technologies of light energy manipulation. One of the most...

All-dielectric nanophotonics attracts more and more attention nowadays due to the possibility to control and configure light scattering on high-index semiconductor nanoparticles. It opens a room of opportunities for the designing novel types of nanoscale elements and devices, and paves a way to advanced technologies of light energy manipulation. On...

In order to boost the performance of magnetic resonance imaging without increasing the static magnetic field, it is necessary to increase its intrinsic sensitivity. This allows a reduction in the scanning time, increased spatial resolution, and can enable low-field strength systems (which are much cheaper and can be used to scan patients with metal...

Wireless power transfer is a breakthrough technology which can be used in all aspects of humans daily life. Here, a bi-layer metasurface as a transmitter for near-field wireless power transfer is proposed and studied. The novelty and advantage of the proposed metasurface is the spatial separation of the electric and magnetic near fields. Magnetic f...

In this contribution we present numerical and experimental results of a parametric quantitative study of radiative dipole antennas in a phased array configuration for efficient body magnetic resonance imaging at 7 T via parallel transmission. For magnetic resonance imaging (MRI) at ultrahigh fields (7 T and higher) dipole antennas are commonly used...

Nanostructures made of high-index semiconductors (n > 2.5) with the several orders of magnitude lower losses than noble metals possess (Au, Ag, Pt etc.) are gaining high interest in recent years for various advanced optical applications, including nanothermometry and optical heating. Owing to the high-Q of Mie-optical modes that are being supported...

We report on the design and the numerical and experimental characterization of an all-dielectric reflecting focusing metasurface (metamirror) which does not have a back reflector, but effectively reflects incident waves with the desired reflection phase gradient. The profile of the reflection phase can be tuned independently for both sides of the s...

In this contribution, we present a new radio-frequency probe, a dual dielectric resonator used for transmissionand reception of RF signals in Magnetic Resonance Microscopy.The probe is designed as a pair of magnetically coupled ceramicrings with the permittivity of 530 resonating at the Larmorfrequency of protons at the magnetic field 17 T (730 MHz...

We report on a design of metasurface formed by parallel conducting wires for wireless power transfer system. The metasurface being exited by a dielectric resonator guides the power to the receiving resonator. We both numerically and experimentally demonstrate that a stable power transfer efficiency of 83% can be achieved over the distance up to 100...

In the Supplementary Material, we prove the validity of the dipole-quadrupole approximation to obtain the conditions of the transverse scattering. The coincidence of the electric dipole Fano profile with the quadrupoles off-resonance and their role in obtaining the transverse scattering phenomenon have been clarified. We also investigate the substr...

All-dielectric resonant nanophotonics lies at the heart of modern optics and nanotechnology due to the unique possibilities to control scattering of light from high-index dielectric nanoparticles and metasurfaces. One of the important concepts of dielectric Mie-resonant nanophotonics is associated with the Kerker effect that drives the unidirection...

The spatial resolution and signal‐to‐noise ratio (SNR) attainable in magnetic resonance microscopy (MRM) are limited by intrinsic probe losses and probe–sample interactions. In this work, the possibility to exceed the SNR of a standard solenoid coil by more than a factor‐of‐two is demonstrated theoretically and experimentally. This improvement is a...

We propose the concept of and experimentally demonstrate a metasurface-based smart table for wireless power transfer. The proposed structure supports propagating surface modes that can be excited by the near field of wireless devices. As a result, if two devices are placed anywhere on a metasurface table, a substantial enhancement of the effective...

Increasing the strength of the static magnetic field is the main trend in modern magnetic resonance imaging (MRI) of humans. Performing MRI in ultrahigh fields (7 T or more) involves many effects both enhancing and diminishing the image quality, and some effects previously unobservable in weaker fields. We review the main impacts of using ultrahigh...

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 chargin...

This work studies the guided localized electromagnetic waves propagating along finite and infinite chains of parallel thin resonant wires periodically arranged over an interface of a dielectric half-space. Both issues of guided wave propagation in an infinite chain and resonant excitation of hybridized eigenmodes of a finite chain are solved analyt...

A hybrid metasurface realized by a double array of brass wires inserted into two high-permittivity dielectric slabs at both sides was used to perform a magnetic resonance spectroscopy experiment at a 1.5T clinical magnetic resonance scanner. The metasurface coupled inductively to a transceive birdcage body coil located within the scanner’s bore. Th...

Increasing the static magnetic field strength into the realm of ultrahigh fields (7 T and higher) is the central trend in modern magnetic resonance (MR) imaging. The use of ultrahigh fields in MR-imaging leads to numerous effects some of them raising the image quality, some degrading, some previously undetected in lower fields. This review aims to...

In this work we explore photonic topological edge states arising in dielectric metasurface based on a deformed honeycomb lattice. We demonstrate numerically the effect of pseudo-spin locking of the edge states and verify its existence experimentally in microwave frequency range. Our findings thus demonstrate that open non-Hermitian metasurface can...

Metamaterial-inspired resonator for a wireless power transfer system is proposed and studied numerically. The resonator consists of two orthogonal wire layers separated by a short distance. To reduce the resonant frequency from several hundreds of MHz it is placed in a background dielectric material with high permittivity. By tuning the permittivit...

We demonstrate the results of on THz emission from hybrid THz photoconductive antenna loaded with silver nanoantenna. The results of experimental investigations are in a good agreement with numerical simulations presented in our recent work. The conversion efficiency reveals over 5-fold improvement at certain frequencies, if compared with similar p...

All-dielectric resonant nanophotonics has attracted a lot of interest due to unique possibilities to control scattering of light in high-index dielectric nanoparticles and metasurfaces. One of the important concepts of dielectric meta-optics and nanophotonics is associated with the Kerker effect that drives the unidirectional scattering of light fo...

In this work, we propose and discuss methods of tuning eigenmode resonance frequencies of wire metasurfaces. Fine tuning of metasurface properties is essential for maximizing its coupling with transmitting and receiving radiofrequency (RF) coils of a magnetic resonance imaging (MRI) system. We have studied numerically and experimentally two designs...

Recently self-complementary frequency-selective surfaces (FSSs) have been shown capable of linear-to-circular polarization transformation. In this work we numerically and experimentally prove generality of this approach showing that similar self-complementary tessellations can be used as FSS patterns in both the microwave and the sub-millimeter wav...

Guided localized electromagnetic waves propagating along 1D arrays of thin metallic parallel wires, finite and infinite, are studied. The array of thin PEC wires is embedded in the upper dielectric half-space close to the interface separating two dielectric media with different permittivities. In the first part of the work we study dependence of re...

Metasurfaces due to their ability to individually sculpt the near-field patterns over a frequency range from radio to optical recommended themselves as good candidates for image quality enhancement that is crucially important in different areas including biology, medicine, and nanotechnologies. Particularly, one important practical application of m...

In this work we demonstrate a comparative study of the a new proposed coil based on periodic capacitively-loaded thin wires and a conventional loop coil both optimized for small-animal imaging applications at 7 Tesla. The proposed coil uses hybridized eigenmodes of the flat periodic array comprising a number of thin metal wires, excited by a small...

In this paper, we propose, design and test a new dual-nuclei RF-coil inspired by wire metamaterial structures. The coil operates as a result of resonant excitation of hybridized eigenmodes in multimode flat periodic structures comprising several coupled thin metal strips. It was shown that the field distribution of the coil (i.e. penetration depth)...

Advanced nanophotonics penetrates into other areas of science and technology, ranging from applied physics to biology and resulting in many fascinating cross-disciplinary applications. It has been recently demonstrated that suitably engineered light-matter interactions at the nanoscale can overcome the limitations of today's terahertz (THz) photoco...

Topological phase transitions in condensed matter systems give rise to exotic states of matter such as topological insulators, superconductors, and superfluids. Photonic topological systems open a whole new realm of research and technological opportunities, exhibiting a number of important distinctions from their condensed matter counterparts. Phot...

Purpose: Design and characterization of a new inductively driven wireless coil (WLC) for wrist imaging at 1.5 T with high homogeneity operating due to focusing the B1 field of a birdcage body coil. Methods: The WLC design has been proposed based on a volumetric self-resonant periodic structure of inductively coupled split-loop resonators with st...

We present all-dielectric resonant structured surfaces for the realization of lossless compact photonic topological metadevices. We demonstrate spin-Hall effect of light for spin-polarized topological edge states through proof-of-concept near-field spectroscopy measurements.

Achieving efficient localization of white light at the nanoscale is a major challenge due to the diffraction limit, and nanoscale emitters generating light with a broadband spectrum require complicated engineering. Here we suggest a simple, highly efficient nanoscale white-light source based on a hybrid Si/Au nanoparticle with ultrabroadband (1.3--...

Metasurfaces represent a new paradigm in artificial subwavelength structures due to their potential to overcome many challenges typically associated with bulk metamaterials. The ability making very thin structures and change their properties dynamically make metasurfaces an exceptional meta-optics platform for engineering advanced electromagnetic a...

Metasurfaces represent a new paradigm in artificial subwavelength structures due to their potential to overcome many challenges typically associated with bulk metamaterials. The ability making very thin structures and change their properties dynamically make metasurfaces an exceptional meta-optics platform for engineering advanced electromagnetic a...

Plasmonic nanoparticles coupled with metallic films forming nanometer scale cavities have recently emerged as a powerful tool for enhancement of light-matter interaction. Despite high efficiency for sensing and light emission, such nanocavities exhibit harmful and uncontrolled optical heating which limits the ranges of light intensities and working...

In this work, we experimentally demonstrate an increase in the local transmit efficiency of a 1.5 T MRI scanner by using a metasurface formed by an array of brass wires embedded in a high permittivity low loss medium. Placement of such a structure inside the scanner results in strong coupling of the radiofrequency field produced by the body coil wi...

All-dielectric nanophotonics based on high-index dielectric nanoparticles became a powerful platform for modern light science, providing many fascinating applications, including high-efficient nanoantennas and metamaterials. High-index dielectric nanostructures are of a special interest for nonlinear nanophotonics, where they demonstrate special ty...

We present the results of hybrid photoconductive antenna THz emission enhanced by silver nanoantenna arrays. By varying the size of nanoantennas and the distance between them, we obtain the greatest value of optical-to-THz conversion efficiency reached so far. The results of experimental investigations are in a good agreement with numerical simulat...

We design and analyze photo-metamaterials with each meta-atom containing both photodiode and light-emitting diode. Illumination of the photodiode by the light-emitting diode gives rise to an additional optical feedback within each unit cell, which strongly affects resonant properties and nonlinear response of the meta-atom. In particular, we demons...

We design and analyze photo-metamaterials with each meta-atom containing both photodiode and light-emitting diode. Illumination of the photodiode by the light-emitting diode gives rise to an additional optical feedback within each unit cell, which strongly affects resonant properties and nonlinear response of the meta-atom. In particular, we demons...