Metamodelling in the information field

The article studies metamodelling in the information field. Specifics of metamodelling are described. Three basic interpretations of metamodelling are shown. The features of metamodelling in information technologies and information field are presented. A functional difference between the information space and the information field is specified. The article studies metarelations in the information field. Three information situations characterizing metarelations are considered: sequence, transformation, and generalization. The differences in metarelations between an object and a metamodel and between a model and a metamodel are described. The article shows the relation scheme in the system "object – model – metamodel". The scheme of metatheory formation is presented. The principles of metamodelling in the information field are revealed. The article proves that a metamodel in the information field is a model of information construction. A new concept of information metamodelling is introduced

All-dielectric magnetic metasurface for advanced light control in dual polarizations combined with high-Q resonances

Nanostructured magnetic materials provide an efficient tool for light manipulation on sub-nanosecond and sub-micron scales, and allow for the observation of the novel effects which are fundamentally impossible in smooth films. For many cases of practical importance, it is vital to observe the magneto-optical intensity modulation in a dual-polarization regime. However, the nanostructures reported on up to date usually utilize a transverse Kerr effect and thus provide light modulation only for p-polarized light. We present a concept of a transparent magnetic metasurface to solve this problem, and demonstrate a novel mechanism for magneto-optical modulation. A 2D array of bismuth-substituted iron-garnet nanopillars on an ultrathin iron-garnet slab forms a metasurface supporting quasi-waveguide mode excitation. In contrast to plasmonic structures, the all-dielectric magnetic metasurface is shown to exhibit much higher transparency and superior quality-factor resonances, followed by a multifold increase in light intensity modulation. The existence of a wide variety of excited mode types allows for advanced light control: transmittance of both p- and s-polarized illumination becomes sensitive to the medium magnetization, something that is fundamentally impossible in smooth magnetic films. The proposed metasurface is very promising for sensing, magnetometry and light modulation applications

TMOKE as efficient tool for the magneto-optic analysis of ultra-thin magnetic films

Ultra-thin magnetic dielectric films are of prime importance due to their applications for nanophotonics and spintronics. Here, we propose an efficient method for the magneto-optical investigation of ultra-thin magnetic films which allows one to access their state of magnetization and magneto-optical properties. It is based on the surface-plasmon-polariton-assisted transverse magneto-optical Kerr effect (TMOKE). In our experiments, sub-100 nm-thick bismuth-substituted lutetium iron-garnet films covered with a plasmonic gold grating have been analyzed. The excitation of surface plasmon-polaritons provides resonance enhancement of TMOKE up to 0.04 and makes it easily detectable in the experiment. For films thicker than 40 nm, the TMOKE marginally depends on the film thickness. A further decrease in the film thickness diminishes TMOKE since for such thicknesses the surface plasmon-polariton field partly penetrates inside the non-magnetic substrate. Nevertheless, the TMOKE remains measurable even for few-nm-thick films, which makes this technique unique for the magneto-optical study of ultra-thin films. Particularly, the proposed method reveals that the off-diagonal components of the magnetic film permittivity tensor grow slightly with the reduction of the film thickness.Comment: 5 page

Controlling the Transverse Magneto-Optical Kerr Effect in Cr/NiFe Bilayer Thin Films by Changing the Thicknesses of the Cr Layer

Here, we demonstrate the impact of ferromagnetic layer coating on controlling the magneto-optical response. We found that the transverse magneto-optical Kerr effect (TMOKE) signal and TMOKE hysteresis loops of Ni80Fe20 thin layers coated with a Cr layer show a strong dependence on the thickness of the Cr layer and the incidence angle of the light. The transmission and reflection spectra were measured over a range of incidence angles and with different wavelengths so as to determine the layers’ optical parameters and to explain the TMOKE behavior. The generalized magneto-optical and ellipsometry (GMOE) model based on modified Abeles characteristic matrices was used to examine the agreement between the experimental and theoretical results. A comprehensive theoretical and experimental analysis reveals the possibility to create a TMOKE suppression/enhancement coating at specific controllable incidence angles. This has potential for applications in optical microscopy and sensors

TMOKE enhancement in structured all-dielectric iron-garnet films with waveguide modes

The idea of using nanostructured all-dielectric structures to enhance magneto-optical effects instead of plasmonic ones is attracting much interest. The use of dielectric materials allows one to avoid significant energy losses that are present in metals. In this paper, an experimental research of TMOKE effect in 1D dielectric magnetic structures was performed. Experimental results demonstrate a significant enhancement of TMOKE, as well as a high transparency and high Q-factor of the obtained resonances, which opens up broad opportunities for the use of such structures as light modulators

Enhancement of magnetooptical effects in nanostructured iron-garnet meta-surface

The excitation of propagating modes in nanostructured materials is well known to enhance the magnetooptical effects. We propose a novel iron-garnet meta-surface structure and study experimentally the multifold increase of magnetooptical effects in it due to excitation of optical surface waveguide modes. Magnetic meta-surface is fabricated as magnetophotonic crystals with 1D periodicity achieved by etching of 300-nm thick bismuth-substituted iron-garnet film

Resonances of the Faraday Effect in Nanostructured Iron Garnet Films

Magnetic nanostructures make it possible to enhance magneto-optical effects by many times owing to the excitation of optical resonances. A new type of magnetic structure is proposed, which is a two-dimensional all-dielectric bismuth-substituted iron garnet grating. Enhancement of the Faraday effect in such a structure caused by the excitation of waveguide modes is described analytically, and the conditions for the resonant enhancement are revealed. The resonant enhancement of the Faraday effect in all-dielectric magnetic nanostructures has been experimentally demonstrated for the first time

Enhancement of the magneto-optical response in ultra-thin ferromagnetic films and Its registration using the transverse magneto-optical kerr effect

Enhancement of the magneto-optical response in ultra-thin ferromagnetic films (less than 100 nm thick) is studied using the transverse magneto-optical Kerr effect. The gyration of the material increases as the film grows thinner, though the Kerr effect itself may wane