Using the magneto-optical Kerr effect to study magnetization processes in two-dimensional magnonic crystals based on YIG thin films

The magneto-optical Kerr effect for red (628 nm) and green (532 nm) light is used to study magnetization processes in 2D magnonic crystals obtained by etching pits with the diameter D ≈ 32 μm to a depth of t ≤ 2 μm in a 16.1-μm-thick film of yttrium iron garnet (YIG). Hysteresis loops obtained in the case of the inplane crystal magnetization at 628 nm are characterized by lower saturation fields H _s and higher remanent magnetizations than those obtained at 532 nm, a result that is attributed to different absorption coefficients of the YIG film at these wavelengths. This difference between the magnetization curves reflects the fact that the magnonic-crystal surface probed with the green light makes a greater contribution to the magneto-optical Kerr effect. Therefore, the green light is more sensitive to the demagnetizing fields, which govern magnetization processes in the magnonic crystals.     

A magneto-optical setup for studying the time evolution of nanoscale domain-wall displacements under pulsed magnetization

A magneto-optical setup for studying the time evolution of nanoscale domain-wall displacements of domain walls in magnetic films with a regular domain structure is described. Methods for spatial filtering of the output optical flux using the Fourier image of the domain structure and the impulse transient response in the real-time mode are applied in the setup. This allowed an increase in the sensitivity to domain-wall displacements of up to 5 nm and registration of their evolution with a temporal resolution of 1 ns.     

Simulation of the properties of a single-polarization microstructured optical fiber

For the first time, the properties of a single-polarization microstructured fiber exhibited over a broad spectral range have been numerically simulated. The simulation was performed via the multipole method adapted to asymmetric structures. A structure with the highest values of birefringence and dichroism known to date has been proposed and investigated.     

Narrowband surface-acoustic-wave filters in RF identification systems

Low-loss narrowband surface-acoustic-wave filters designed for operation in RF identification devices in the frequency range 860–890 MHz are developed and investigated. Software is developed on the basis of the theory of coupled modes. A procedure for calculating a resonator transversely coupled structure is presented. This procedure provides good agreement between experimental and theoretical results. The manufactured filters are based on the resonance structures made on single-crystal quartz substrates by means of liftoff (explosive) photolithography and a batch-fabrication technique.     

Anomalous Doppler effect observed during propagation of magnetostatic waves in ferromagnetic films and ferrite-dielectric-metal structures

The anomalous Doppler effect observed during propagation of magnetostatic backward volume waves in a free ferromagnetic film and magnetostatic surface waves in a ferrite-dielectric-metal structure is investigated. The effect is theoretically substantiated, and plots of Doppler frequency shift are constructed. The anomalous Doppler effect is qualitatively analyzed with the use of equifrequency curves.     

Concepts of scaling and fractal dimension in the design of a fractal detector of radio signals

Concepts of hardware implementation of fractal nonparametric detectors of radar signals (FNDRSs) are analyzed. The structure of the first FNDRS prototype is determined on the basis of concepts of sample topology and fractal signatures. Experiments in which frequency and time scalings are used for detection of sinusoidal and pulsed signals in the presence of additive noises and interferences on the basis of a 1D sample are conducted with the FNDRS prototype. Probabilities of correct detection are calculated and the classic accumulation mode is compared with the new method of fractal filtering. The studies are conducted as part of program “Fractal Radio Systems Designed for Different Purposes and Fractal Components” proposed by and developed at the Institute of Radio Engineering and Electronics (IREE) of the Russian Academy of Sciences.     

Tunable band gaps in a layered structure magnonic crystal-ferroelectric

A dispersion relation for a hybrid electromagnetic-spin wave in a layered structure magnonic crystal-ferroelectric has been derived. The main distinctions of the band gaps in this structure from those in a single magnonic crystal have been determined. It is shown that the characteristics of these zones can be tuning by the electric field.     

Isolated-word segmentation based on the dynamics of the parameters of short correlation functions

The theoretical and experimental results obtained in an investigation of the dynamic behavior of short-correlation-function parameters and applied to the problem of speech-signal segmentation are described. The side maxima of the correlation functions of various quasi-periodic signals are investigated theoretically. Their dependences on the characteristics that determine the degree of signal quasi-periodicity are presented. These dependences are used to construct instrumental estimates of the degree of such parameters as the quasiperiodicity, the duration of quasi-periodicity segments, and the fundamental-tone period. The obtained estimates are interpreted for the case of voice signals, and it is shown that many important procedures used in speech technologies can be implemented on the basis of these estimates.     

Surface-acoustic-wave filters with a high input power for a nominal frequency of 2170 MHz for communication systems and radar and telecommunications equipment

The basic design of microwave filters based on surface acoustic waves with a high input power for specialized communication systems and radar and telecommunications equipment is developed.