卷 89, 编号 1 (2025)

We theoretically and numerically investigate the optical implementation of the second-order spatial differentiation operation using a layered metal-dielectric structure at normal light beam incidence. Numerical simulation results confirm the theoretical results and show the possibility of ‘optical calculation of the Laplace operator with high quality.

An expression is obtained that allows us to determine the law of dispersion of plasma waves ω(𝑘) in a two-dimensional semiconductor superlattice under the influence of a nonlinear electromagnetic wave and, in the extreme case of weak nonlinearity, an analytical expression for ω(𝑘) is found. The possibility of controlling the frequency of the plasma wave by the parameters of a nonlinear wave has been established.

An analysis of superluminal propagation of resonant and quasi-resonant soliton-like laser pulses in non-equilibrium media is presented. It is shown that such pulses are unstable. However, at the initial stage of instability development, it is possible to observe superluminal propagation of these pulse profiles due to the reshaping mechanism.

Using numerical 2D-PIC simulations, the generation of X-rays during the interaction of an oncoming laser wave with a relativistic electron mirror formed by a powerful accelerating laser pulse from a plasma layer is investigated. The structure of the radiated field in the far zone is investigated, the spectral density of the radiation field and the angular distribution of the pulse energy are found. Changing the parameters of the accelerating and counter waves allows one to control the characteristics of the radiation.

The possibility to exploit nonlinear Fabry–Perot interferometers to differential gain of terahertz radiation in the field of a pump wave of the same frequency was theoretically considered. It is shown that in mirrorless nonlinear Fabry–Perot interferometer consisted of crystalline quartz plate, which reflection is determined by Fresnel reflection only, the regime of maximal differential gain of radiation with central frequency at 1 THz can be observed at thickness of working medium near 1 mm and at radiation intensity with order of magnitude at 108 W⋅cm−2.

We discussed the authors’ recent research into the generation and ultrafast control of light-induced dynamic microcavities and photonic time crystals created by the collision of half-cycle pulses in a medium. The possibility of guiding microcavities during the collision of self-induced transparency half-cycle pulses of the same polarity has been demonstrated.

A scheme for implementing a microwave photonics receiving device for microwave signals for the formation and registration of radio holograms is proposed. The operation of such a receiving device was studied numerically and experimentally. A data processing method is proposed to reduce the error in determining the source coordinates.

The results of a study of the effect of two-dimensional phenomena on the electron beam bunching in single-beam and multi-beam broadband klystrons are presented. The results of a comparative analysis of beam bunching using a one-dimensional and two-dimensional model are presented. The causes of errors in determining the output parameters of broadband klystrons obtained using one-dimensional programs are analyzed.

The problem of nonstationary diffraction of a monopolar TM-polarized electromagnetic pulse with a flat front on a thin slit in a perfectly conducting screen is considered. Using computational experiment methods, it has been shown that if the slit width is much smaller than the spatial length of the pulse, then a field is formed behind the screen in the form of a cylindrical monopolar pulse, i. e. there is a transformation of the shape of the incident field front without changing its character (monopolarity).

In the point of view of liquid water as a real gas, the Van der Waals equation of state is modified for describing isotherms, isochores, and isobars of liquid water in a wide range of pressures and temperatures. The new thermal equation provides a standard transition to thermodynamics with the reproduction of internal energy 𝑈, free energy 𝐹, heat capacity 𝐶V and entropy 𝑆.

We simulated the dynamics of electric field impact on the domain wall in magnetic films with inhomogeneous magnetoelectric interaction. The result of the simulation is the fact that both homogeneous electric field and inhomogeneous electric field induce excitation of spin waves.

We proposed a method for local assessment of acoustic properties in spongy polymer samples, based on visualizing the microstructure, measuring attenuation, and sound velocity. This approach is relevant to the study of biopolymer composite materials and their structures, as it allows for in situ observation of structural degradation under external influences, as well as investigation of the evolution of native tissue replacement, if necessary.