Dmitry L. Kovalenko

The current paper uses neural network modeling and a genetic algorithm to determine the values of technological parameters that ensure effective laser cleaving of quartz glass when exposed to a laser beam with a wavelength equal to 10.6 µm and a refrigerant. Multi-criteria optimization of laser cleaving of quartz plates was performed according to the criteria of maximum tensile stresses and maximum processing speed.

The purpose of this work is to build the analytical model of the behavior of a harmonic wave in a nonlinear optical medium with periodically arranged nanofilms. Methods. The modernized method is presented of non-smooth transformation of the argument to eliminate the Dirac functions on the right side of the non-linear inhomogeneous differential equation describing linear polarized wave behavior within a non-linear optical medium with periodically arranged conducting nanofilms. Small parameter methods, in particular, the averaging method, is also used to find an approximate analytical solution. Results. The fully analytical model of the behavior of a linear polarized harmonic wave within a nonlinear optical medium with periodically arranged conducting nanofilms is constructed. Conclusion. For the case of propagation of a linearly polarized harmonic wave in a nonlinear optical medium with periodically arranged conducting nanofilms, the mathematical model based on the non-smooth argument transformation method is constructed. The model is fully analytical, all expressions are obtained directly from Maxwell’s equations by identical transformations. The limits of its applicability are determined by the limits of application of the wave theory of light.

In this work, we have investigated the photocurrent and spectral sensitivity of the silicon/SrTiO₃:xNb/perovskite structures. The sol–gel method carried out the deposition of undoped SrTiO₃ layers as well as niobium-doped (SrTiO₃:Nb) layers at atomic concentrations of 3 and 6% Nb. The perovskite layer, CH₃NH₃PbI_3−xCl_x, has been deposited by the vacuum co-evaporation technique. The layers have been characterized by scanning electron microscopy and X-ray diffraction measurements. The volt–ampere characteristics and spectral sensitivity of the fabricated samples have been measured under illumination with selective wavelengths of 405, 450, 520, 660, 780, 808, 905, 980, and 1064 nm of laser diodes. We have shown that for different configurations of applied voltage between silicon, SrTiO₃:xNb, and CH₃NH₃PbI_3−xCl_x, the structures are photosensitive ones with a variation of photocurrent from microamperes to milliamperes depending on Nb concentration in SrTiO₃, and the highest photocurrent and spectral sensitivity values are observed when a SrTiO₃:Nb layer with 3 at.% of Nb is used. A possible application of the proposed structure with a SrTiO₃:Nb layer for perovskite solar cells and photodetectors is being discussed.