Vol 88, No 2 (2024)

We propose a design and show the numerical simulation results for a W-band (75–110 GHz) phase shifter. The structure of the phase shifter consists of periodic array of rectangular patch antennas on a dielectric substrate with built-in pin-diodes. The calculations demonstrate the possibility of achieving a phase shift of the transmitted wave up to 87° at a frequency of 96 GHz with transmittance losses of –7 dB.

Experimental investigations of chiral injection AlAs/(Al, Ga)As/GaAs vertical-cavity surface-emitting lasers in the multimode generation regime are performed. A high circular polarization degree > 70% of different generation modes measured with a high spectral resolution, is demonstrated. Detailed maps of spatial and angular distribution of laser radiation intensity were constructed.

Neutral excitations with zero momentum in a Laughlin liquid at an electron filling factor of 1/3 have been studied. It was found that the lowest in energy are spin-magnetogravitons, excitations with a simultaneous change in the electron density in the Laughlin liquid and the spin quantum number of the electron system. The experimental possibility of the formation of new quasi-equilibrium states of anionic matter – Laughlin solutions of spin-magnetogravitons – is demonstrated. A new type of optical scattering is observed in Laughlin solutions.

The electron spin resonance impact on the longitudinal resistance in the quantum Hall regime near the integer filling factors is considered. For the odd filling factors extra spin excitons are created in the process of the microwave absorption, and the resistance increase due to the effective temperature rise. For the even filling factors in the absorption process depending on the temperature inspired spin polarization leads to transition of the spin-flip excitations to the higher energy short-lived excitations, and as a result the resistance is decreased due to effective temperature decrease.

We described the development of a biosensor for the rapid and sensitive detection of botulinum toxin type A. The sensor is a SERS substrate with an optimized concentration of labeled aptamers, immobilized on its surface. It allows the detection of botulinum toxin type A with a detection limit of 2.4 ng/ml in 1 hour.

The temperature dependences of the magnetization of ε-In_0.04Fe_1.96O₃ nanoparticles were measured in the cooling and heating regimes. At a temperature of 150 K, a sharp drop in their magnetization is observed. Evidence is obtained that the observed magnetic phase transition is accompanied by a reversal of the magnetization due to a first-order spin-reorientation transition. The experimental results are described in terms of the thermodynamic approach.

The effect of a vertical electric field on photoluminescence of a MoSe₂ monolayer encapsulated with hexagonal boron nitride is investigated. In the spectra, there is a quadratic shift of the photoluminescence lines of excitons and trions from the applied potential difference, as well as a change in their intensity. It is found that the magnitude of the Stark shift significantly exceeds the theoretically predicted one. It is found that the energy distance between the trion and exciton lines in the spectra varies with the magnitude of the external field, which is due to the dependence of the density of free charge carriers in the monolayer on the field. This effect made it possible to determine the density of free charge carriers in the monolayer, which varies with the field and lies in the range from 0.3–3.4⋅10¹² cm^–2.

Using a canonical quantization, the motion of a micro-particle in a medium with the viscous resistance is analyzed. Localized wave packets of the type of coherent states are considered in detail. It has been established that viscous resistance suppresses the quantum properties of a micro-particle, which makes it possible to consider a viscous medium as a classical device.

The calculation of quadratures arises in many physical and technical applications. In this paper, the best quadrature formulas are selected and their quantitative comparison is carried out on a number of representative examples.

The relaxation decays of photon echo signals in thin zinc oxide films produced by magnetron sputtering have been studied. Echo signals are excited at a wavelength of 800 nm at transitions between quantum levels that arise when excitonic states are localized in quantum-sized structures in the two-photon absorption mode of laser pulses with a wavelength of 800 nm.

Topological laws of the Rayleigh wave scattering on a statistical inhomogeneity of isotropic solid are obtained theoretically in the Rayleigh limit. They are completely defined by the inhomogeneity structure and include the Rayleigh law of scattering as a particular case. They violate the Rayleigh law in the case of a more general inhomogeneity topology, then the Rayleigh one. It enables first to construct theoretically arbitrary spectrum of scattering up to its oscillations and a strong angular anisotropy.

The electron transport of non-equilibrium quasiparticles injected into superconducting aluminum from a normal metal has been experimentally studied at ultralow temperatures. We studied hybrid nanostructures in the form of a T-shaped normal metal electrode (copper) – a dielectric tunnel layer (aluminum oxide) – a superconducting fork (aluminum), which can be considered as a solid-state analogues of a two-beam optical interferometer. At fixed bias voltages larger than the superconducting gap, a non-monotonic dependence of the tunnel current on perpendicular magnetic field is observed. The effect is interpreted as the presence of a coherent component of the quasiparticle current.

For remote identification of the processes of powerful solar activity in the form of CME directed towards the Earth, a technique of flicker noise spectroscopy has been developed. The results of the analysis of geo-effective events (> G1) are presented according to the data of the international network of neutron monitors and the multidirectional muon hodoscope URAGAN, which indicate the appearance of predictors (with an outstrip of 1–2 days) of the CME approach to the Earthʼs orbit.

Since 2022, the Institute of Cosmophysical Research and Aeronomy (SB RAS) for the first time has been continuously monitoring the forecast of terrestrial winds of space weather based on data from neutron monitors in Yakutsk and Tiksi. Preliminary studies during periods of geomagnetic disturbances in 2022. The peculiarity is that the results of this may provide an additional opportunity for their use for the purpose of forecasting large geomagnetic storms.

The results of studying the relative abundances and energy spectra of ⁴He, C, O, and Fe suprathermal ions in particle fluxes from long-lived near-equatorial coronal holes are presented. It was found that the ion energy spectra had a power or exponential form and, in a number of events, increased particle fluxes were observed in the region of ion energies (~0.2–1.5 MeV/nucleon), creating a fracture in the spectra, which may be due to additional ions accelerated beyond 1 au.

The TUS detector is a highly sensitive orbital telescope. Due to the polar orbit of the spacecraft, the detector made observations of the UV luminosity of the atmosphere above the aurora oval. Events with intensity variations characteristic of pulsating auroras have been registered. The events are located along the equatorial boundary of the auroral oval and occur during long-term geomagnetic disturbances. Comparison with data from charged particle detectors shows the presence of an increased flux of precipitating high-energy electrons (with energies above 100 keV) simultaneously with UV pulsations.