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Vol 89, No 2 (2025)
New Materials and Technologies for Security Systems
Electromagnetic field amplification in a resonator in the sub terahertz frequency range
Abstract
We presented a numerical simulation of planar resonators for the subterahertz frequency range, confined by various types of reflectors: Bragg mirrors, grating mirrors, solid metal mirrors. The dependences of the amplification of the electric field strength in the resonator on the structure parameters were constructed for normal incidence of an electromagnetic wave on the surface of the resonator. The physical limitations imposed on the magnitude of the gain are determined.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):168–173
168–173
Two-dimensional plasma excitations in a split-ring resonator
Abstract
We analyzed the electromagnetic properties of a split-ring resonator based on a two-dimensional electronic system (2DES). Analysis of the absorption of electromagnetic radiation by the 2DES in the geometry of a split-ring resonator revealed new plasma modes associated with a split in the structure. This plasmon resonance manifests itself under conditions of excitation by both alternating electric and alternating magnetic fields, which opens the possibility of developing a highly efficient tunable phase shifting element.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):174–179
174–179
Low frequency properties of a silicon-based plasmonic detector
Abstract
The properties of a silicon-based plasmonic detector of electromagnetic radiation were examined in the lowfrequency region (0.1-20 GHz). The detector’s sensitive element was embedded within a matched coplanar waveguide, through which the electromagnetic radiation was conveyed. The dependence of the DC voltage observed at the detector’s output on the frequency of the incident radiation was measured. The detector’s power characteristics were measured, and the threshold radiation power at which the detector transitions into a nonlinear regime was determined.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):180–183
180–183
The response time of a silicon-based plasmonic detector
Abstract
The response time of a silicon-based plasmonic detector of electromagnetic radiation was investigated. For this purpose, frequency mixing experiments were carried out in the microwave frequency range. The sensitive element of the detector was embedded in the slits of a matched coplanar waveguide. The response time τ = 60±10 ps was estimated from the attenuation of the signal amplitude with increasing the difference frequency.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):184–187
184–187
Phase diagram of magnetoexciton condensate
Abstract
The phase boundary of the “gas – magnetoexciton condensate” transition of an excited two-dimensional electron system placed in a quantizing magnetic field is constructed in the “temperature – excitation density” coordinates. Based on experimental data, it can be concluded that the condensate is a collective, incompressible in real space, excited state of a Hall dielectric.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):188–194
188–194
Revealing plasmaron dynamics at filling factors from 1 to 2
Abstract
We investigated the photoluminescence spectrum of two-dimensional electron systems in the filling factor range from 1 to 2 at a temperature of 40 mK. Plasmaron peaks have been identified and their restructuring observed at filling factor 4/3. At high pumping power, additional peaks, dubbed “double plasmarons” were detected, indicating complex interactions within the system.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):195–199
195–199
Magnetic phase transitions and collective effects in MgZnO/ZnO heterostructures
Abstract
We presented the results of a study of two-dimensional electron systems implemented in MgZnO/ZnO heterostructures with high interaction parameters. Using the inelastic light scattering method, we observed ferromagnetic transitions and spin textures. We also studied the dispersion dependences of key energy parameters.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):200–203
200–203
Study of temporal dynamics of photo-reflection signal at the fractional filling factor ν = 1/3 in the second time range
Abstract
The temporal dynamics of the photo-reflection signal was studied at a fractional filling factor of twodimensional electrons ν = 1/3 in a GaAs quantum well at liquid helium temperatures T ≈ 0.6 K. It has been demonstrated that using a modified photon-counting technique it is possible to measure relaxation times of excitations in a Laughlin liquid of the order of 100 seconds.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):204–206
204–206
Resonance photoluminescence of the excited Laughlin liquid
Abstract
The resonance photoluminescence of excited Laughlin liquid at the electron filling factor of 1/3 is studied. It is shown that for a neutral defect in Laughlin liquid consisting of an electron at the upper spin sublevel of the zero Landau level and a valence hole, the influence of random potential fluctuations on the probability of optical recombination of the defect is suppressed (random potential superscreening). Filling the Laughlin liquid with single-spin excitations (spin-magnetogravitons) does not affect this observation.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):207–210
207–210
Luminescence of MoSe2: effect of temperature and pumping value
Abstract
The luminescence of excitons and trions in a MoSe monolayer encapsulated with hBN was studied under non-resonant photoexcitation of electron-hole pairs depending on the temperature and pumping intensity. The shift of luminescence lines and the redistribution of intensities can be explained by the influence of both the Fermi gas of free electrons and localized states of electrons caused by the presence of impurities in boron nitride hBN.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):211–214
211–214
Excited states of excitons in monolayers of transition metal dichalcogenides in reflectance spectra up to room temperature
Abstract
The ground and excited states of A- and B-excitons in monolayers of MoSe2 and WSe2 were studied by optical reflectance spectroscopy in a wide range of temperatures up to room temperature. It has been shown that excited states are observed in the spectrum even at room temperature. Depending on the selected parameters of the heterostructure, the B-exciton line may be comparable in intensity to the A-exciton line.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):215–219
215–219
Reflectance spectra of two-dimensional excitons in heterostructures with MoSe2 and WSe2 monolayers
Abstract
A method of reflection and transmission spectroscopy of heterostructures with MoSe2 and WSe2 monolayers were developed and mastered. The obtained spectra were compared with microphotoluminescence spectra. It was shown that the trion line, which dominates in the microphotoluminescence spectra, is absent in the reflection spectra. The dependence of the reflection spectra on the thickness of the encapsulating layers is also presented.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):220–225
220–225
Oscillations of a giant enhancement of inelastic light scattering in periodic plasmonic structures as a function of metallic film thickness
Abstract
It was discovered that in metallic films with periodic holes (the size of the square hole was half the period) the effect of a giant enhancement of the intensity of inelastic light scattering is observed, and the enhancement coefficient depends significantly on the thickness of the metal (silver). It is shown that when the thickness of the silver film changes in the range from 5 nm to 140 nm, strong oscillations of the enhancement coefficient are observed, and the amplitude of the oscillations can be more than an order of magnitude. The observed oscillations are explained in terms of the resonant excitation of standing plasmon-polariton waves in metal films, which dispersion varies significantly with variation of the metal thickness.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):226–231
226–231
Investigation of the possibility of using island SERS-structures on a GaP substrate for surface-enhanced inelastic light scattering in the infrared frequency range
Abstract
We studied the properties of GaP-based periodic dielectric structures with a silver layer coating which can enhance the signal of surface-enhanced inelastic light scattering (SERS). The dependences of the scattering signal intensity on the period for different structure heights were obtained. A comparison of the scattering signal intensities for SiO2 and GaP SERS-structures for laser excitation wavelengths of 532, 785 and 1064 nm was performed. The ability of GaP-based structures with a thin metal layer to enhance the signal by more than 7 orders of magnitude in the infrared frequency range was found. The dependence of the Raman signal enhancement on the thickness of the deposited layer was studied.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):232–236
232–236
Gold nanoparticles as SERS-substrates for MTT assay
Abstract
Several variants of gold nanoparticles were proposed for the detection of formazan formed because of enzymatic reduction of the MTT reagent by E. coli enzymes. It is shown that gold nanostars coated with a micellar stabilizer are the most promising SERS-substrate for the detection of formazan in biological mixtures, reducing the required titer of bacteria by at least an order of magnitude.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):237–246
237–246
Study of the capabilities of Raman spectroscopy in identifying the content of total hemoglobin in human blood
Abstract
The possibility of using Raman spectroscopy in determining the total hemoglobin content in the blood was investigated. It has been established that a few lines in the Raman spectrum linearly depend on the hemoglobin concentration. It has been shown that SERS using silver colloids also gives a linear concentration dependence on the intensity of spectral lines
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):247–255
247–255
Development of SERS active track-etched membranes with high sustainability in biological fluids
Abstract
Different approaches for creating an enhancing surface based on a track-etched polyethylene terephthalate membrane are studied. The stability of the covering and the potential for the usage of the obtained substrates were evaluated on the example of the aptasensor for the determination of the influenza A virus.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):256–264
256–264
Dynamics of spinor exciton-polariton condensates in double potential traps in a GaAs/AlAs microcavity under resonant picosecond excitation
Abstract
The temporal evolution of the polarized emission spectra of spinor exciton-polariton condensates in double tunnel-coupled potential traps in a high-Q GaAs/AlAs microcavity at 2 K under resonant laser pumping with picosecond pulses has been studied in the time range up to 1.5 ns. An estimate of the spin relaxation time of the condensate τS ∼ 10 ns is obtained. The influence of the symmetry of the trap potential on the energy spectrum of the polariton modes and on the polarization dynamics of the spinor condensate in the tunnel-coupled potential traps is discussed.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):265–273
265–273
Self-oscillatory and chaotic states of a polariton system in a size-quantized cavity micropillar
Abstract
Theoretical study is performed of a quasi-two-dimensional exciton-polariton system localized in a circular microcavity mesa under the conditions of resonant photoexcitation. It is predicted that in a case when several size-quantized sublevels are excited, a series of transitions occurs from stationary to self-oscillatory and further to chaotic states. The transition from stationary states to oscillations is accompanied by a lowering of the rotational symmetry down to a discrete one, whereas in the chaotic region the spatial symmetry disappears completely. In a spinor system, analogous phenomena result in polarization chaos.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):274–279
274–279
Experimental studies of the generation thresholds of circularly polarized еmission from injection semiconductor lasers
Abstract
The dependences of the radiation intensity in various circular polarizations from injection surface-emitting lasers with a vertical chiral microresonator on the excitation current value were experimentally investigated. A sharp increase of the circular polarization degree of the laser emission from small values of ≈ 5 % to the values of <70% was observed at a current exceeding the threshold value. Considering the nonlinear optical properties of laser resonators model calculations were performed, the calculation results are in good agreement with the experiment.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):280–285
280–285
Studies of spin-phonon interaction in magnetic topological insulators MnBi2Te4 by Raman spectroscopy
Abstract
Experimental studies of Raman scattering spectra in single crystals of topological magnetic insulators MnBi2Te4 have been performed in a wide temperature range. The influence of spin-phonon interaction on the studied spectra at temperatures below the antiferromagnetic phase transition temperature is discussed.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):286–289
286–289
Raman scattering in ferromagnetic Ge1−xCox nanowires
Abstract
Correlation of the temperature dependencies of Raman scattering and ferromagnetic resonance is found in nanowires of a dilute magnetic semiconductor Ge0.99Co0.01. A sudden softening of the optical phonons lines occurs at T ≈ 74 K. The observed behavior indicates a strong interaction of carriers not only with phonons, but also with the magnetic system.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):294–298
294–298
Raman scattering in ferromagnetic Ge1−xMnx nanowires
Abstract
The temperature dependence of Raman scattering is investigated in nanowires of a dilute magnetic semiconductor Ge0.99Mn0.01. It was found that with increasing temperature, a red shift (“softening”) of the optical LO-phonon line occurs at T ≈ 25 K. The observed behaviour correlates with the data of the electron paramagnetic resonance of mobile charge carriers and indicates a strong interaction of holes with the phonon and magnetic subsystems.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):290–293
290–293
Surface enhanced Raman scattering on grids with submicron silver coating
Abstract
A new method for obtaining effective grid substrates with a nanostructured silver coating by electrodeposition from an electrolyte solution for the study of Raman-active molecules by surface-enhanced Raman scattering (SERS) without a chemically passive separation layer is proposed. The amplification effect is two orders of magnitude higher than the amplification in the so-called “hot spots” of metal substrates before silver coating.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):299–304
299–304
Wave Phenomena: Physics and Applications
Waves and fine structures of physical variables in a viscous stratified liquid
Abstract
The surface perturbation in a viscous, stratified liquid is investigated in a two-dimensional setting. Expressions for the dynamics of periodic surface motion and the fine-scale structure of currents are derived. Distributions of the wave and ligament components of the density, density gradients, and pressure are constructed. A fine structure accompanying the wave component of the flow is identified in physically measurable variables.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):306–313
306–313
Current structure in the Black Bay of the Kandalaksha Bay during different phases of the tidal cycle
Abstract
We presented the results of in-situ measurements of currents in the Black Bay of Kandalaksha Bay in 2021–2023, which is subject to tidal influence. The surface and bottom currents in different phases of the tidal cycle were measured using a grid of stations, the area in which the current from Nilmo-guba is registered was determined, and the in-situ measurements were compared with the results of modeling of bottom currents.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):314–319
314–319
Using the geometric properties of three invariants in the wave equation for the electric field strength
Abstract
In Euler’s work Principia motus fluidorum, the continuity equation for a fluid is derived using high-order terms of smallness that contain the quadratic and cubic invariants of the strain rate tensor. From Maxwell’s system of electrodynamics equations, the wave equation for the electric field strength is derived taking into account the quadratic and cubic invariants. These invariants describe the generation of electric field intensity waves.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):320–327
320–327
Spatial variation of superconducting order parameters in thin aluminum films
Abstract
Oscillations of the order parameter arising because of spatial quantization of electronic states in a quantum well formed by the walls of a thin film of superconducting aluminum were theoretically studied. In such objects, with decreasing thickness, a noticeable increase of critical temperature and broadening of superconducting transition are observed. These effects are interpreted as the manifestation of quantum size effect that affects the density of states of electrons and, hence, other various electronic properties of thin films.
Izvestiâ Akademii nauk SSSR. Seriâ fizičeskaâ. 2025;89(2):328–332
328–332