Ivan S. Maksymov

All-optical switching in 2D silicon photonic crystals with low loss waveguides and optical cavities

A study of the optical transmission of low-loss W1.5 photonic crystal waveguides built on silicon membranes and operating at telecom wavelengths is presented. The feasibility of performing all-optical switching is demonstrated for W1.5 waveguides coupled with L3 cavities, systems amenable for incorporation in on-chip devices. Switching of waveguide transmission is achieved by means of optical excitation of free carriers using a 2.5 ns pump laser. Experimental results are reproduced by finite-difference time-domain simulations which model the response of the finite system and band structure calculations describing the infinite, ideal one.

Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Magneto-Dielectric Nanostructures

A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin waves. Moreover, readers interested in a new, rapidly emerging field of all-dielectric nanophotonics will find a section about all-magneto-dielectric nanostructures.

Microwave eddy-current shielding effect in metallic films and periodic nanostructures of sub-skin-depth thicknesses and its impact on stripline ferromagnetic resonance spectroscopy

A strong microwave shielding effect due to the excitation of microwave eddy-currents exists for metallic films of sub-skin-depth thickness (10–100 nm). If the film is ferromagnetic, this effect strongly influences results of the broadband stripline ferromagnetic resonance (FMR) spectroscopy. It also potentially hampers the development of magnetically tuneable metamaterials. By means of rigorous numerical simulations, we address an important problem of the dependence of the eddy current effect on the width of the stripline used for driving magnetisation dynamics in the broadband FMR spectroscopy. We study theoretically electrodynamics of realistic striplines and also extend the main result from the case of continuous conductive films to periodic conductive nanostructures—magnonic crystals. Based on these findings, we also give recommendations on improving performance of magnetically tuneable metamaterials, which are based on conductive ferromagnetic films and nanostructures. In our simulations, we consider...

Sensing magnetic nanoparticles using nano-confined ferromagnetic resonances in a magnonic crystal

We experimentally demonstrate the use of the magnetic-field-dependence of highly spatially confined, GHz-frequency ferromagnetic resonances for the detection of magnetic nanoparticles using an anti-dot-based magnonic crystal. The stray magnetic fields of nanoparticles within the anti-dots modify nano-confined ferromagnetic resonances in the surrounding periodically nanopatterned magnonic crystal, generating easily measurable resonance peak shifts. The shifts are comparable to the resonance linewidths for high anti-dot filling fractions with their signs and magnitudes dependent upon the mode localization, consistent with micromagnetic simulation results. This is an encouraging result for the development of frequency-based nanoparticle detectors for nano-scale biosensing.

Impact of conducting nonmagnetic layers on the magnetization dynamics in thin-film magnetic nanostructures

Through rigorous numerical simulations with an improved finite-difference time-domain algorithm consistent with a linearized Landau-Lifshitz-Gilbert equation and Hoffmann interlayer exchange boundary conditions, we investigate theoretically broadband ferromagnetic resonance response of single-layer and bilayer magnetic film nanostructures closely contacting with nonmagnetic metal layers. We show that the nonmagnetic capping/seed layers decrease the nonuniformity of the magnetic field inside the magnetic films, which decreases the effect of dominating first higher-order standing spin-wave mode observable in broadband ferromagnetic resonance spectrometry. We also demonstrate that the conductivity of a microstrip line inducing a microwave Oersted field in the magnetic films insignificantly affects the frequency and linewidth of the resonances. However, it exerts a shielding effect on the magnetic field and thus reduces the amplitude of the resonance peaks. Finally, we argue that in experiments involving spin wave detection in insulating magnetic films via the inverse spin-Hall effect voltage, the platinum electrode should be placed away from the microstrip line. Our findings will be useful for the design and optimization of spintronic devices for spin-based data-storage and processing.

Plasmon-assisted high reflectivity and strong magneto-optical Kerr effect in permalloy gratings

We demonstrate experimentally a strong plasmon-assisted enhancement of the transverse magneto-optical Kerr effect in permalloy gratings. The enhanced transverse magneto-optical Kerr effect is accompanied by an increased grating reflectivity with the maximum of enhancement being correlated with plasmonic Fano resonances. This correlation was confirmed by an intuitive Fano model and also through full-vectorial optical simulations. Simultaneously high reflectivity and transverse magneto-optical Kerr effect as well as narrowest ferromagnetic resonance linewidth and vanishing anisotropy make permalloy nanostructures attractive for applications in spintronics and nano-optics such as, for example, all-optical excitation of propagating spin waves and spectral tuning of optical nanoantennas.

Plasmonic nanoantennas for efficient control of polarization-entangled photon pairs

We suggest a source of polarization-entangled photon pairs based on a cross-shaped plasmonic nanoantenna driven by a single quantum dot. The integration of the nanoantenna with a metal mirror overcomes the fundamental tradeoff between the spontaneous emission (SE) enhancement and the extraction efficiency typical of microcavity- and nanowire-based architectures. With a very high extraction efficiency of entangled photons (≈90%) at 1.55 μm and large SE enhancement (≈90) over a broad 330-nm spectral range, the proposed design will pave the way toward reliable integrated sources of nonclassical light.

The analytical basis for the resonances and anti-resonances of loop antennas and meta-material ring resonators

Interest in the electromagnetic properties of loop structures has surged with the recent appearance of split-ring resonator meta-materials (SRRs) and nano-antennas. Understanding the resonances, anti-resonances, and harmonics of these loops is key to understanding their response to a wide range of excitation wavelengths. We present the classical analytical solution for the input impedance of a loop structure with circumference on the order of the wavelength, and we show how to identify these resonances from the function. We transform the classical solution into a new RLC formulation and show that each natural mode of the loop can be represented as a series resonant circuit, such that the full response function can be resolved by placing all of these circuits in parallel. We show how this formulation applies to SRRs.

Microwave magnetic dynamics in ferromagnetic metallic nanostructures lacking inversion symmetry

In this work, we carried out systematic experimental and theoretical investigations of ferromagnetic resonance (FMR) responses of quasi-two-dimensional magnetic objects—macroscopically long stripes with nanoscale cross-section made of ferromagnetic metals. We were interested in the impact of the symmetries of this geometry on the FMR response. Three possible scenarios from which the inversion symmetry break originated were investigated, namely: (1) from the shape of the stripe cross-section, (2) from the double-layer structure of the stripes with exchange coupling between the layers, and (3) from the single-side incidence of the microwave magnetic field on the plane of the stripe array. The latter scenario is a characteristic of the stripline FMR configuration. It was found that the combined effect of the three symmetry breaks is much stronger than the impacts of each of these symmetry breaks separately.

Rigorous numerical study of strong microwave photon-magnon coupling in all-dielectric magnetic multilayers

We demonstrate theoretically a ∼350-fold local enhancement of the intensity of the in-plane microwave magnetic field in multilayered structures made from a magneto-insulating yttrium iron garnet (YIG) layer sandwiched between two non-magnetic layers with a high dielectric constant matching that of YIG. The enhancement is predicted for the excitation regime when the microwave magnetic field is induced inside the multilayer by the transducer of a stripline Broadband Ferromagnetic Resonance (BFMR) setup. By means of a rigorous numerical solution of the Landau-Lifshitz-Gilbert equation consistently with the Maxwells equations, we investigate the magnetisation dynamics in the multilayer. We reveal a strong photon-magnon coupling, which manifests itself as anti-crossing of the ferromagnetic resonance magnon mode supported by the YIG layer and the electromagnetic resonance mode supported by the whole multilayered structure. The frequency of the magnon mode depends on the external static magnetic field, which in our case is applied tangentially to the multilayer in the direction perpendicular to the microwave magnetic field induced by the stripline of the BFMR setup. The frequency of the electromagnetic mode is independent of the static magnetic field. Consequently, the predicted photon-magnon coupling is sensitive to the applied magnetic field and thus can be used in magnetically tuneable metamaterials based on simultaneously negative permittivity and permeability achievable thanks to the YIG layer. We also suggest that the predicted photon-magnon coupling may find applications in microwave quantum information systems.