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.

Direct observation of the transition from spin waves to the magnon Bose condensate.

Bose-Einstein condensation occurs at an appropriate density of bosonic particles, depending on their mass and temperature. The transition from the semiclassical paradigm of spin waves to the magnon Bose-Einstein condensed state (mBEC) was obtained experimentally with increasing magnon density. We used the Faraday rotation effect to study the spatial distribution of the magnon density and phase far from their excitation region.

Tunable broadband transmittance and Faraday effect in a magnetophotonic nanostructure with gradient thickness.

We propose a magnetic photonic crystal (MPC) nanostructure with a gradient thickness of the magnetic layer. Such a nanostructure exhibits on-the-fly adjustment of optical and magneto-optical (MO) properties. Spatial displacement of the input beam allows tuning of the spectral position of the defect mode resonance in the bandgap of both transmission and magneto-optical spectra.

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 transverse magnetization under excitation of 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. Plasmonic dichroism is similar to circular magnetic dichroism, which is at the base of all-optical helicity-dependent switching (AO-HDS) but observed for linearly polarized light, and the dichroism acts upon in-plane magnetized films, where AO-HDS does not take place.

Topological Faraday Effect for Optical Vortices in Magnetic Films.

Here we experimentally demonstrate the topological Faraday effect-the polarization rotation caused by the orbital angular momentum of light. It is found that the Faraday effect of the optical vortex beam passing through a transparent magnetic dielectric film differs from the Faraday effect for a plane wave. The additional contribution to the Faraday rotation depends linearly on the topological charge and radial number of the beam.

Optical registration of a coherent magnon state outside of the excitation region.

Magnons have demonstrated enormous potential for the next generation of information technology and quantum computing. In particular, the coherent state of magnons resulting from their Bose-Einstein condensation (mBEC) is of great interest. Typically, mBEC is formed in the magnon excitation region.

Magneto-Optical Spectroscopy of Short Spin Waves by All-Dielectric Metasurface.

The optical method of spin dynamics measurements via the detection of various magneto-optical effects is widely used nowadays. Besides it being a convenient method to achieve time-resolved measurements, its spatial resolution in the lateral direction is limited by a diffraction limit for the probe light. We propose a novel approach utilizing a Mie-resonance-based all-dielectric metasurface that allows for the extraction of a signal of a single submicron-wavelength spin wave from the wide spin precession spectra.

Faraday effect in magnetoplasmonic nanostructures with spatial modulation of magnetization.

For the first time, to the best of our knowledge, the properties of the Faraday effect are addressed in a magnetoplasmonic nanostructure with nonuniform spatial distribution of the magnetization. It is shown that the coincidence in period and phase between magnetization modulation and the field of the optical mode provides the resonant enhancement of the Faraday effect. This effect is observed for both the surface plasmon polariton and waveguide modes.

Design of an Artificial Opal/Photonic Crystal Interface for Alcohol Intoxication Assessment: Capillary Condensation in Pores and Photonic Materials Work Together.

Alcohol intoxication has a dangerous effect on human health and is often associated with a risk of catastrophic injuries and alcohol-related crimes. A demand to address this problem adheres to the design of new sensor systems for the real-time monitoring of exhaled breath. We introduce a new sensor system based on a porous hydrophilic layer of submicron silica particles (SiO SMPs) placed on a one-dimensional photonic crystal made of TaO/SiO dielectric layers whose operation relies on detecting changes in the position of surface wave resonance during capillary condensation in pores.

Silver Nanopillar Arrayed Thin Films with Highly Surface-Enhanced Raman Scattering for Ultrasensitive Detection.

Surface-enhanced Raman scattering (SERS) technique based on surface plasmon resonance has been considerably investigated in recent years due to its superior sensitivity in the detection of organic or biological molecules at trace levels. However, most research usually focuses on artificial architectures as SERS substrates that always have a complex and expensive micro-nanofabrication process. The high cost of masks for SERS substrates becomes a key obstacle for the widespread commercialization of SERS technology.

Spatially selective excitation of spin dynamics in magneto-photonic crystals by spectrally tunable ultrashort laser pulses.

In this work, we tackle the problem of the spatially selective optical excitation of spin dynamics in structures with multiple magnetic layers. The 120 fs circularly polarized laser pulses were used to launch magnetization precession in an all-dielectric magneto-photonic crystals (MPC) formed by magnetic layers sandwiched between and inside two magnetic Bragg mirrors. Optical pump-probe experiments reveal magnetization precession triggered via ultrafast inverse Faraday effect with an amplitude strongly dependent on the pump central wavelength: maxima of the amplitude are achieved for the wavelength tuned at the cavity resonance and at the edge of the photonic bandgap.

Accumulation and control of spin waves in magnonic dielectric microresonators by a comb of ultrashort laser pulses.

Spin waves in magnetic microresonators are at the core of modern magnonics. Here we demonstrate a new method of tunable excitation of different spin wave modes in magnetic microdisks by using a train of laser pulses coming at a repetition rate higher than the decay rate of spin precession. The microdisks are etched in a transparent bismuth iron garnet film and the light pulses influence the spins nonthermally through the inverse Faraday effect.

Magneto-optical imaging of coherent spin dynamics in ferrites.

The explosive development of quantum magnonics is associated with the possibility of its use as macroscopic quantum systems. In particular, they can find an application for quantum computing processors and other devices. The recently discovered phenomenon of magnon Bose-Einstein condensation and coherent precession of magnetization can be used for these purposes.

Spectrally Selective Detection of Short Spin Waves in Magnetoplasmonic Nanostructures via the Magneto-Optical Intensity Effect.

A method of spectrally selective detection of short spin waves (or magnons) by means of the transverse magneto-optical (MO) intensity effect in transmission in the magnetoplasmonic nanostructure is proposed. We considered the spin waves with a wavelength equal to or less than (by an integer number of times) the period of the plasmonic structure, that is, of the order of hundreds of nanometers or 1-2 μm. The method is based on the analysis of the MO effect spectrum versus the modulation of the sample magnetization (created by the spin wave) and related spatial symmetry breaking in the magnetic layer.

Magnetic nanoribbons with embedded cobalt grown inside single-walled carbon nanotubes.

Molecular magnetism and specifically magnetic molecules have recently gained plenty of attention as key elements for quantum technologies, information processing, and spintronics. Transition to the nanoscale and implementation of ordered structures with defined parameters is crucial for advanced applications. Single-walled carbon nanotubes (SWCNTs) provide natural one-dimensional confinement that can be implemented for encapsulation, nanosynthesis, and polymerization of molecules into nanoribbons.

Silicon-Based All-Dielectric Metasurface on an Iron Garnet Film for Efficient Magneto-Optical Light Modulation in Near IR Range.

All-dielectric nanostructures provide a unique low-loss platform for efficiently increasing light-matter interaction via excitation of the localized or propagating optical modes. Here, we report on the transverse magneto-optical Kerr effect enhancement in an all-dielectric metasurface based on a two-dimensional array of Si nanodisks on a cerium substituted dysprosium iron garnet thin film. We observed up to 15% light intensity modulation under TM modes excitation.

Magnetization Switching in the GdFeCo Films with In-Plane Anisotropy via Femtosecond Laser Pulses.

Ferrimagnetic rare-earth substituted metal alloys GdFeCo were shown to exhibit the phenomenon of all-optical magnetization switching via femtosecond laser pulses. All-optical magnetization switching has been comprehensively investigated in out-of-plane magnetized GdFeCo films; however, the films with the in-plane magnetic anisotropy have not yet been studied in detail. We report experimental observations of the magnetization switching of in-plane magnetized GdFeCo films by means of the femtosecond laser pulses in the presence of a small magnetic field of about 40 µT.

Two-dimensional array of iron-garnet nanocylinders supporting localized and lattice modes for the broadband boosted magneto-optics.

We demonstrate a novel all-dielectric magnetophotonic structure that consists of two-dimensional arrays of bismuth substituted iron-garnet nanocylinders supporting both localized (Fabry-Perot-like) and lattice (guided-like) optical modes. Simultaneous excitation of the two kinds of modes provides a significant enhancement of the Faraday effect by 3 times and transverse magneto-optical Kerr effect by an order of magnitude compared to the smooth magnetic film of the same effective thickness. Both magneto-optical effects are boosted in wide spectral and angular ranges making the nanocylinder array magnetic dielectric structures promising for applications with short and tightly focused laser pulses.

Multiperiodic magnetoplasmonic gratings fabricated by the pulse force nanolithography.

We propose a novel, to the best of our knowledge, technique for 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 surface plasmon polaritons excitation efficiency by varying the grating parameters such as the scratching depth or the number of scratches in a single period.

Quantum paradigm of the foldover magnetic resonance.

The explosive development of quantum magnonics requires the consideration of several previously known effects from a new angle. In particular, taking into account the quantum behavior of magnons is essential at high excitations of the magnetic system, under the conditions of the so-called phenomenon of "foldover" (bi-stable) magnetic resonance. Previously, this effect was considered in the quasi-classical macrospin approximation.

Sensing of Surface and Bulk Refractive Index Using Magnetophotonic Crystal with Hybrid Magneto-Optical Response.

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical response that allows for the simultaneous measurements of the surface and bulk refractive index of the analyzed substance. The approach is based on two different spectral features of the magneto-optical response corresponding to the resonances in p- and s-polarizations of the incident light. Angular spectra of p-polarized light have a step-like behavior near the total internal reflection angle which position is sensitive to the bulk refractive index.

Nanophotonic structures with optical surface modes for tunable spin current generation.

We propose a novel type of photonic-crystal (PC)-based nanostructures for efficient and tunable optically-induced spin current generation via the spin Seebeck and inverse spin Hall effects. It has been experimentally demonstrated that optical surface modes localized at the PC surface covered by ferromagnetic layer and materials with giant spin-orbit coupling (SOC) notably increase the efficiency of the optically-induced spin current generation, and provides its tunability by modifying the light wavelength or angle of incidence. Up to 100% of the incident light power can be transferred to heat within the SOC layer and, therefore, to the spin current.

Plasmon and Plexciton Driven Interfacial Catalytic Reactions.

In this review, we focus on the summary of catalytic reaction driven by surface plasmons and plexciton, where the plexciton is the interaction between plasmon and exciton. We first review the reduction and oxidation reactions driven by plasmons, and analyze the role of plasmons in the two reactions. We then summarize the recent research on the surface catalytic reactions driven by plasmon-exciton coupling and discuss the promotion effect of coupling interaction in oxidation reaction and reduction reaction.

Layer-selective magnetization switching in the chirped photonic crystal with GdFeCo.

Here we propose a magnetophotonic structure for the layer-selective magnetization switching with femtosecond laser pulses of different wavelengths. It is based on a chirped magnetophotonic crystal (MPC) containing magnetic GdFeCo and nonmagnetic dielectric layers. At each operating wavelength the laser pulses heat up to necessary level only one GdFeCo layer that leads to its magnetization reversal without any impact on the magnetization of the other layers.

Bound states in the continuum enable modulation of light intensity in the Faraday configuration.

We demonstrate a novel, to the best of our knowledge, magneto-optical effect that reveals itself in light intensity modulation without polarization rotation in the Faraday configuration. We design a photonic crystal with a magnetized optical cavity that supports bound states in the continuum (BICs), since it simultaneously provides the extended state (continuum) for TM polarization, and the bound (localized) state in the form of a cavity mode for TE-polarized light. Magnetization of the photonic crystal in the Faraday configuration results in efficient polarization conversion and trapping of the acquired TE components of the TM incident light inside the magnetized optical cavity.