arXiv subjects

Vladimir I. Belotelov

Publications and source records attributed to Vladimir I. Belotelov.

At least 19 recordsLinked to original sources

arXiv2026

Magneto-optical intensity effect in a transparent perforated all-dielectric metasurface with an anapole state

We numerically study a perforated all-dielectric metasurface based on the magnetic semiconductor GaMnAs. Near the anapole state, the structure combines high transmittance with a moderate magneto-optical intensity effect. The absolute transmission modulation is enhanced by about a factor of five compared with a smooth film, while the metasurface transmittance reaches 81%. The enhancement is associated with strong field localization in the magneto-optically active material and suppression of the electric-dipole radiation channel in the anapole regime.

physics.optics↗

arXiv2026

Single-pulse strain-induced precessional dynamics of magnetization in Co-doped iron garnet

Ultrafast control of magnetization through lattice excitation provides a route to manipulating magnetic order on short timescales, yet the role of transient strain in driving magnetization dynamics remains poorly understood. Here, single-shot pump-probe magneto-optical microscopy is used to resolve the structural and magnetic responses of cobalt-doped yttrium iron garnet to individual 5-ps mid-infrared pulses. The excitation generates a localized strain field together with an outward-propagating elastic wave. Concurrently, the magnetic contrast decreases following excitation and subsequently reverses on a timescale of approximately 1.5-2 ns before recovering to its initial state. The structural and magnetic responses exhibit closely correlated wavelength and pulse-energy dependences, indicating a common excitation pathway. Micromagnetic simulations incorporating transient strain reproduce the precessional reorientation of the magnetization within individual domains while largely preserving the labyrinthine domain morphology. These results identify transient lattice deformation as the link between single-pulse mid-infrared excitation and reversible precessional magnetization dynamics in Co-doped yttrium iron garnet.

cond-mat.mtrl-sci↗

arXiv2026

Magnetophotonic crystals with antiferromagnetic order

We investigate a magnetophotonic crystal formed by the pairs of layers with the opposite out-of-plane magnetization. Despite vanishing total magnetization such antiferromagnetic pattern opens photonic bandgap, gives rise to nontrivial topological phases and enables strong cross-polarized light reflection at frequencies inside the gap which can be harnessed for magnetically tunable polarization-rotating mirrors. We systematically explore optical properties of this structure highlighting fruitful connections to topological photonics and axion electrodynamics.

physics.optics↗

arXiv2025

Photo-induced switching of magnetisation in the epsilon-near-zero regime

The possibility of controlling spins using ultrashort light and strain pulses has triggered intense discussions about the mechanisms responsible for magnetic re-ordering. All-optical magnetisation switching can be achieved through ultrafast heat-driven demagnetisation or transient modifications of magnetic anisotropy. During the phononic switching of magnetic dielectrics, however, mid-infrared optical excitations can modify the crystal environment via both the thermal quenching of anisotropy and the generation of strain respectively, with the relative distinction between these thermal and non-thermal processes remaining an open question. Here, we examine the effect of mid-infrared pulses tuned to the frequency of optical phonon resonances on the labyrinthine domain structure of a cobalt-doped yttrium iron garnet film. We find that the labyrinthine domains are transformed into stable parallel stripes, and quantitative micromagnetic calculations demonstrate this stems predominantly from a partial quenching of the anisotropy. Contrary to conventional wisdom, however, we find that this heat-facilitated process of magnetisation switching is spectrally strongest not at the maximum of absorbed optical energy but rather at the epsilon-near-zero points. Our results reveal that the epsilon-near-zero condition provides an alternative pathway for laser-driven control of magnetisation, even when the underlying mechanism is primarily thermal.

cond-mat.mtrl-sci↗

arXiv2025

All-dielectric Metaphotonics for Advanced THz Control of Spins

While nearly single cycle THz pulse is conventionally accepted as the stimulus for the fastest and the most energy efficient control of spins in magnets, all-dielectric metasurfaces have been recently demonstrated to be the least dissipative mean to enhance and control the coupling of light to spins. All-dielectric metasurfaces for the THz control of spins hold great potential in the field of spintronics and related technologies, pushing the boundaries of speed and energy efficiency in spin-based information processing. Here we demonstrate such a metasurface for an advanced THz control of spins in a ferrimagnetic film of iron garnet. Structuring a nonmagnetic substrate one can force a THz electromagnetic field, otherwise described by plane waves, to acquire an out-of-plane magnetic field and thus enable arbitrary direction of the torque acting on spins in all three dimensions. Hence, metaphotonics opens up a plethora of opportunities for advanced control of spins at THz rates in many hot fields of contemporary science, including spintronics, magnonics and quantum computing.

physics.optics↗

arXiv2024

Magnetophotonic waveguide nanostructure for selective ultrafast optical excitation of high-K spin dynamics

Optomagnonics provides a promising method of a Joule-loss-free spin control that can be performed at ultrafast timescale. However, the cornerstone of optomagnonics is impossibility to focus the light tighter than a diffraction limit. This constrains minimal size of the optically switched magnetic bits and minimal wavelengths of the optically excited spin waves in optomagnonic devices thus preventing its further progress. Here we propose and experimentally demonstrate a novel method of the selective optical excitation of the short exchange spin waves by using a specially designed magnetophotonic grating. This method is based on the creation of the sign-changing profile of the inverse Faraday effect (IFE) induced in a magnetic film due to excitation of the optical guided TE-mode by a femtosecond laser pulse. The spatial period of the IFE profile is subdiffractive which allows to launch narrow band short spin waves whose wavelengths are around 300 nm as was experimentally demonstrated and potentially can be made down to ~ 100 nm. This opens new horizons for optomagnetic applications that are wide ranging, from logical elements to data processing devices.

physics.optics↗

arXiv2024

The inverse Faraday effect at Mie resonances

Nowadays, dielectric nanophotonics enables almost lossless resonant interaction between light and matter at the nanoscale. We show both theoretically and by electromagnetic simulations, that the peculiar nature of Mie-resonance induced effective magnetic fields contrasts sharply with the optomagnetism of smooth bulk materials. Mie resonances produce strongly nonuniform effective magnetic fields generated by the inverse Faraday effect. Different orders of optical resonances are characterized by different types of the effective magnetic field patterns. The number of point-like inverse Faraday effect sources can be controlled by adjusting the pump wavelength, allowing for the selective launch of spin waves with submicron wavelengths. A distinguish feature of the Mie-resonance-induced effective magnetic fields is the vortex structure that can be used for the magnetic skyrmion generation. The proposed approach considerably broadens the scope of nanoscale optomagnetism.

physics.optics↗

arXiv2024

Control of a ferrimagnet phase by a two-component magnetic field

We report a theoretical study of the phase diagram of a ferrimagnetic iron-garnet with uniaxial anisotropy near a magnetization compensation point in the presence of a two-component magnetic field. The study is performed based on a quasi-antiferromagnetic approximation. The number and stability of the equilibrium states of the Neel vector are analyzed using the effective energy function. It is shown that application of the small out-of-plane magnetic field in addition to the stronger in-plane magnetic field significantly changes the equilibrium states of a ferrimagnet. The possibilities to control the equilibrium Neel vector position and to switch between the monostable and bistable states by tuning the value and ratio of the in-plane and out-of-plane magnetic field components are demonstrated. This opens new possibilities for the utilization of ferrimagnets since the magnetic field could be changed much faster than the temperature.

cond-mat.mtrl-sci↗

arXiv2023

Optical excitation of multiple standing spin modes in 3D optomagnonic nanocavities

We report the first experimental observation of multiple standing spin modes in 3D optomagnonic nanocavity formed by nanometer-sized iron-garnet nanocylinder. We show that launching of standing spin modes is achieved due to a high confinement of the optically generated effective magnetic field caused by the localized optical resonance. Quantization and spin-wave mode inhomogeneity is achieved in each of the three spatial dimensions. The presented approach opens new horizons of 3D optomagnonics by combining nanophotonic and magnonic functionalities within a single nanocavity.

physics.optics↗

arXiv2023

Spatially inhomogeneous inverse Faraday effect provides tunable nonthermal excitation of exchange dominated spin waves

We demonstrate optical nonthermal excitation of exchange dominated spin waves of different orders in a magnetophotonic crystal. The magnetophotonic structure consists of a thin magnetic film and a Bragg stack of nonmagnetic layers to provide a proper nonuniform interference pattern of the inverse Faraday effect induced by light in the magnetic layer. We found a phenomenon of the pronounced phase slippage of the inverse Faraday effect distribution when the pump wavelength is within the photonic band gap of the structure. It allows to tune the interference pattern by a slight variation of light wavelength which results in the modification of excitation efficiency of the different order spin waves. The approach can be applied for different magnetic dielectrics expanding their application horizons for spin-wave based devices.

physics.optics↗

arXiv2022

Plasmonic dichroism and all-optical magnetization switching in nanophotonic structures with GdFeCo

We report on a phenomenon of plasmonic dichroism observed in magnetic materials with the transverse magnetization under the excitation of the surface plasmon polariton waves. The effect originates from the interplay of the two magnetization-dependent contributions to the material absorption, both of which are enhanced under plasmon excitation. Similar to the recently discovered effect of a all-optical helicity-dependent magnetization switching, this effect provides a possibility to perform a deterministic magnetization switching to the desired state. We show by electromagnetic modeling that laser pulses exciting counter-propagating plasmons can be used to write +M or -M state in a deterministic way independent on the initial magnetization state. The presented approach applies to various ferrimagnetic materials exhibiting the phenomenon of all-optical switching of thermal nature and broadens the horizons of their applications in data storage devices.

physics.optics↗

arXiv2021

Magnetophotonics for sensing and magnetometry towards industrial applications

Magnetic nanostructures sustaining different kinds of optical modes have been used for magnetometry and label-free ultrasensitive refractive index probing, where the main challenge is the realization of compact devices able to transfer this technology from research laboratories to smart industry. This Perspective discusses the state-of-the-art and emerging trends in realizing innovative sensors containing new architectures and materials exploiting the unique ability to actively manipulate their optical properties using an externally applied magnetic field. In addition to the well-established use of propagating and localized plasmonic fields, in the so-called magnetoplasmonics, we identified a new potential of the all-dielectric platforms for sensing to overcome losses inherent to metallic components. In describing recent advances, emphasis is placed on several feasible industrial applications, trying to give our vision on the future of this promising field of research merging optics, magnetism, and nanotechnology.

physics.optics↗

arXiv2021

Magneto-optics of the 2D iron-garnet nanocylinder array with localized and lattice modes

We experimentally show the enhancement of the Faraday and transverse magneto-optical Kerr effects in the two-dimensional arrays of nanocylinders made of bismuth-substituted iron-garnet and supporting both localized and lattice modes. Simultaneous excitation of these modes makes it possible to increase the Faraday rotation by 3 times and TMOKE by an order of magnitude compared to the smooth magnetic film of the equal effective thickness. Both magneto-optical effects are enhanced in wide spectral and angular ranges making the nanocylinder array magnetic dielectric structures promising for applications with short and tightly-focused laser pulses.

physics.optics↗

arXiv2021

Circular displacement current induced anomalous magneto-optical effects in high index Mie resonators

Dielectric Mie nanoresonators showing strong light-matter interaction at the nanoscale may enable new functionality in photonic devices. Recently, strong magneto-optical effects have been observed in magneto-optical nanophotonic devices due to the electromagnetic field localization. However, most reports so far have been focused on the enhancement of conventional magneto-optical effects. Here, we report the observation of circular displacement current induced anomalous magneto-optical effects in high-index-contrast Si/Ce:YIG/YIG/SiO2 Mie resonators. In particular, giant modulation of light intensity in transverse magnetic configuration up to 6.4 % under s-polarized incidence appears, which is non-existent in planar magneto-optical thin films. Apart from that, we observe a large rotation of transmitted light polarization in the longitudinal magnetic configuration under near normal incidence conditions, which is two orders of magnitude higher than for a planar magneto-optical thin film. These phenomena are essentially originated from the unique circular displacement current when exciting the magnetic resonance modes in the Mie resonators, which changes the incident electric field direction locally. Our work indicates an uncharted territory of light polarization control based on the complex modal profiles in all-dielectric magneto-optical Mie resonators and metasurfaces, which opens the door for versatile control of light propagation by magnetization for a variety of applications in vectoral magnetic field and biosensing, free space non-reciprocal photonic devices, magneto-optical imaging and optomagnetic memories.

physics.optics↗

arXiv2021

Multiperiodic magnetoplasmonic gratings fabricated by the pulse force nanolithography

We propose a novel technique for the magnetoplasmonic nanostructures fabrication based on the pulse force nanolithography method. It allows one to create the high-quality magnetoplasmonic nanostructures that have lower total losses than the gratings made by the electron beam lithography. The method provides control of the SPP excitation efficiency by varying the grating parameters such as the scratching depth or the number of the scratches in a single period. The quality of the plasmonic gratings was estimated by means of the transverse magneto-optical Kerr effect that is extremely sensitive to the finesse of a plasmonic structure.

physics.optics↗

arXiv2019

Efficient acousto-optical light modulation at the mid-infrared spectral range by planar semiconductor structures supporting guided modes

Acousto-optical devices, such as modulators, filters or deflectors, implement a simple and effective way of light modulation and signal processing techniques. However, their operation wavelengths are restricted to visible and near-infrared frequency region due to a quadratic decrease of the efficiency of acousto-optical interaction with the wavelength increase. At the same time, almost all materials with high value of acousto-optic figure of merit are non-transparent at wavelengths larger than 5 μm, while the transparent materials possess significantly lower acousto-optic figure of merit. Here we propose and demonstrate by calculations how these limitations could be overcome using specially designed planar semiconductor structures supporting electromagnetic modes strongly coupled to the incident light in the Otto configuration. Such approach could be used for a novel efficient acousto-optical device operating in middle infrared range of 8-14 μm. Acoustic wave excited by a piezoelectric transducer in a semi-conductor prism is utilized to modulate the coupling coefficient of the incident light to the semiconductor structure which results in up to 100% modulation of the transmitted light at the spatial scale less than the ultrasound wavelength. It allows to utilize acoustic waves with short decay distance and therefore, it provides a unique possibility to achieve an efficient acousto-optical modulation at frequencies over several gigahertz, which are unreachable for traditional acousto-optics.

cond-mat.mtrl-sci↗

arXiv2019

Resonances of the magneto-optical intensity effect mediated by interaction of different modes in a hybrid magnetoplasmonic heterostructure with gold nanoparticles

Here we demonstrate a novel smart magnetoplasmonic heterostructure for efficient control of light. It consists of gold nanoparticles embedded in a thin magnetic film covered with a gold layer pierces with periodic nanoslit array. Unique feature of the proposed structure is that it supports four different types of optical modes in the same frequency range including localized and propagating surface plasmons along with waveguide modes. A peculiar magneto-optical response appears at the frequencies of the mode hybridization. The most prominent result comes from hybridization of the localized and propagating plasmons leading to a significant increase of the magneto-optical intensity effect.

physics.optics↗

arXiv2019

Faraday-Rotation in Iron Garnet Films Beyond Elemental Substitutions

In previous decades significant efforts have been devoted to increasing the magneto-optical efficiency of iron garnet materials for the miniaturization of nonreciprocal devices such as isolators and circulators. Elemental substitutions or proper nano-structuring to benefit from optical resonances have been pursued. However, all these approaches still require film thicknesses of at least several tens of microns to deliver useful device applications, and suffer from narrow bandwidths in the case of optical resonance effects. This Letter reports on a newly discovered enhancement of the Faraday Effect observed experimentally in nanoscale bismuth-substituted iron garnet films. It is shown here that this enhancement is not due to elemental substitution or compositional variations. Nor is it due to photon trapping or resonance effects. Comprehensive experimental and theoretical analysis of the Faraday rotation reveals a dramatic seven-fold amplification in the magneto-optic gyrotropy within only 2 nm of the air-surface interface, corresponding to just a couple of atomic monolayers as a result of symmetry-breaking at the air-film interface. This finding opens up an avenue to the application of monolayer magnetic garnets for the control of light.

physics.optics↗