# Новости

## Section 1 - Track 1

On this page, talks in the format of posters are posted. They can be viewed during the whole time of the Conference. To send your question to the authors, please follow to Miro and write your question in the comments. You can also use the feedback form on our website. Authors will answer questions using Miro comments or via email. To get manual go to Instructions (eng / rus).

Tatiana Plastinina * Modeling the formation of non-diffraction parabolic beams *

All articles, we performed a numerical study of the generalization of parabolic non-diffraction beams of two orders formed from an analytically given distribution of the ring spatial spectrum. The formation and propagation of non-diffraction parabolic beams are simulated using the Fourier transform and the Fresnel transform. The influence of the radius and width of the circular spatial spectrum on the diffraction-free properties of the beams, as well as the nature of the symmetry of the transverse beam patterns depending on the orders of the beam, is studied.

Andrey Ustinov * Peculiarities of the generalized and fractional parabolic beams *

Earlier, we introduced generalized and fractional parabolic beams, and gave a description of their basic properties. This report is devoted to the consideration of not mentioned particular properties of this class of beams, and their theoretical proof. Additional properties that occur when one of the parameters is set to zero are discussed in detail here. We proved that for an integer and a half-integer index, the rotational symmetry of the intensity distribution of the order depending on the index value is manifested. For better visual observation of the rotational symmetry, it is proposed to perform a correction of the angular spectrum in the input plane. It was also proved that for the other values of the index symmetry is not quite strict, and there is an additional rotation of the picture at a certain angle. The value of the angle depends on the index and the distance from the center of the picture. The theoretical conclusions are in good agreement with the results of numerical modeling.

Mikhail Bretsko, Yana Akimova, Yuriy Egorov, Alexander Volyar and Victor Milyukov * Vortex spectrum of perturbed singular beam and informational Shannon entropy *

We demonstrated transformations of vortex beams subjected to sector disturbances in the form of a diaphragm with hard edges. The transformations of the vortex spectra, the orbital angular momentum, and the informational entropy of the perturbed beam are studied. We found that relatively small angular perturbations of the sectors have almost no effect on the OAM, although the information entropy is rapidly increasing due to the birth of new optical vortices caused by diffraction at the edges of the diaphragm.

Yuriy Egorov, Mikhail Bretsko, Yana Akimova and Alexander Volyar * Features of the fine structure of asymmetric TE and TM modes *

This study is devoted to a new section in the field of singular optics - to beams carrying a fractional topological charge. A feature of this type of beams is structural instability, and with the slightest external perturbation, these beams form arrays of optical vortices. These vortices can be connected and, as it were, form an integral picture, or disintegrate due to the fact that during the propagation each of the vortices receives an additional phase incursion. These studies were based on a theoretical calculation and experimental study of the vector structure of beams transporting optical vortices with a fractional topological charge and the proof of the process of forming asymmetric TE (transversely electrical) and TM (transverse magnetic) modes in free space, and the study of the features of their “thin” vector structures in free space.

Oleg Osipov, Dmitry Mishin, Dmitry Panin and Igor Matveev * Investigation of the reflection of plane optical waves from an inhomogeneous nonreciprocal chiral media *

The paper considers an analytical solution of the problem of reflection of optical range plane electromagnetic waves from an inhomogeneous layer of a nonreciprocal chiral media, which is described by a complex coupling coefficient. The problem was solved for incidence of s- and p-polarized waves. Analytical expressions are obtained for the reflection and transmission coefficients of the main and cross-polarized components of the wave field. As a result of numerical simulation, the frequency characteristics of the reflection coefficient moduli of the main and cross-polarized waves are found. It is shown in the work that when a linearly polarized wave is incident, a nonreciprocal chiral layer leads to a rotation of the plane of polarization of the transmitted wave and to the appearance of an elliptical polarization of the reflected wave.

Sergey Lishaev * Investigation of iterative calculation of diffraction-free beams with a given distribution *

An iterative algorithm for calculating the phase diffraction optical element forming a given intensity distribution was considered. The algorithm was developed taking into account the presence of a diffraction-free distribution of the spatial spectrum concentrated in the annular region. The study was carried out by varying the size of the ring in order to find a compromise between the manifestation of a given distribution of diffraction-free properties and the quality of the resulting image.

Evgeny Monin * Comparative study of propagation of Gauss-Laguerre beams and circular Airy beams in a parabolic fiber *

In this paper, a comparative study of the properties of two types of beams-GaussLaguerre and circular Airy beams. It is known that Gauss-Laguerre beams are modes in an optical fiber with a parabolic change in the refractive index, and in free space they retain their structure by changing the scale. On the other hand, circular airy beams, which resemble GaussLaguerre beams in structure, possess autofocus properties. The propagation of two types of beams in a parabolic optical fiber using fractional Fourier transform is considered.

Ilya Rodin * Modeling and researching of propagation of Airy and Pearcey beams *

In given paper we present research of propagation of accelerating Airy and Pearcey beams and their both symmetric and asymmetric modifications. Modeling of propagation was performed with Fourier and Fresnel transformations. Mostly paper is dedicated to research of affect of parameters of input specters on beams non-difractial properties. Also we show an influence of characteristics of input field on formed beams properties and dependence of potential propagation distance and acceleration on focal length, given fields sizes and optical parameters.

Pavel Khorin * The formation of diffraction-free beams with a given distribution based on the Whittaker integral *

In the work, the calculation and study of diffractive optical elements (DOE) for the formation of a diffractionless beam with a given distribution based on the Whittaker integral are performed. To simulate a diffraction-free beam, it is proposed to study the Whittaker integral, as well as to form diffraction-free beams with a given distribution based on an infinitely thin ring.

Victor Kotlyar, Alexey Kovalev and Darya Kalinkina * Spin angular momentum and energy flow density in the sharp focus of a light field with an optical vortex and polarization singularity on the optical axis *

Using the Richards-Wolf formulae, we obtain for a light field with an optical vortex and polarization singularity (radial, azimuthal, or saddle polarization) on the optical axis, expressions for all three components of the spin angular momentum (SAM) density and for the power flow (longitudinal component of the Poynting vector) near the sharp focus of an aplanatic system. As a special case, we investigate focusing of a narrow-ring optical vortex with radial, azimuthal, and saddle polarization. For azimuthal polarization, the SAM is shown to have only the longitudinal component (pure magnetization effect), whereas for saddle polarization, there are areas in the focal plane where the SAM has only the azimuthal transverse component. We also show that if a light field has saddle polarization and a vortex topological charge of three, a reverse power flow arises on the optical axis, several times higher than the direct flow.

Pavel Mokshin, Sergey Kharitonov and Svetlana Khonina * The operation modeling of spectral filters of the THz range using vector Bessel beams *

This article is devoted to modeling the operation of spectral filters based on the use of linearly varying parameters. In this paper, we estimate the size of the scattering spot depending on the parameters of the spectral filter. The results were obtained by decomposing the incident radiation into vector Bessel waves. A numerical calculation showed that a significant deterioration in resolution occurs only in the case of short-focus optical systems.

Sergey Stafeev, Elena Kozlova, Anton Nalimov and Victor Kotlyar * Tight focusing of cylindrical vector beam by gradient index lens *

In this paper we simulated the focusing of a second-order cylindrical vector beam by Mikaelian microlens. It was shown that the lens forms a region of the reverse energy flow near its shadow surface. If the lens has a microhole on the axis, it is possible to localize the region of the direct energy flux inside the lens material and to concentrate the region with the reverse energy flux in free space.

Sergey Stafeev and Victor Kotlyar * Behaviour of transverse Poynting vector components in the vicinity of tight focus *

Using Richards-Wolf formula it was numerically investigated focusing of circularly polarized plane wave with wavelength 532 nm by aplanatic lens with high numerical aperture. We have investigated the behavior of spin energy flow Se = Im[E*×E] and Poynting vector S = Re[E×H*] in focal spot.

Mariia Zablovskaia * Transformation of light beams using waveguides *

In this paper, we studied the transformations of Gaussian-Laguerre beams and Gaussian beams using waveguides. A study was made of the influence of the type of waveguide on the degree of distortion of the beam.

Sergey Volotovskiy * Algorithm for approximating a beam with a given intensity by Hermite-Gaussian modes *

In the optical transmission of information, communication channels can be compressed by superposition of several spatial modes (with given weights carrying information) in one beam at the input of the transmitting system. This problem is quite effectively solved by diffraction optics using various coding methods. At the output of the transmitting system, recognition (detection) of a set of modes contained in the beam is required. In this case, rather complex multi-order optical elements are used, which make it possible to determine only the modulus of the coefficients. Subsequent digital processing is required to recover the relative phases of the coefficients. In this paper, we consider the problem of reconstructing the complex coefficients of the superposition of Hermite-Gaussian modes from the field intensity in a certain plane perpendicular to the propagation axis at a given distance using the Levenberg-Marquardt algorithm.

Alexey Dzyuba * Calculation and research of point spread function in apodized optical system in order to compensate defocus *

It is known that image quality deteriorates noticeably when defocusing or shifting the detection device from the sharpness plane. One way to increase the depth of focus of the optical system and reduce the negative consequences of blurring defocused images is to phase apodize the system, for example, with a cubic phase function. As a rule, apodization is accompanied not only by positive effects (increasing the depth of focus), but also by a significant change in the structure of the point scattering function and the growth of side lobes. Subsequent digital processing can be applied to eliminate the negative effect, but at the same time it is desirable to perform some optimization of the apodizing function, observing a compromise between increasing the depth of focus and distortion of the point scattering function.

Yana Akimova, Mikhail Bretsko, Yuriy Egorov, Alexander Volyar and Victor Milyukov * Digital sorting of perturbed Laguerre-Gaussian modes by radial index *

In this paper, we present digital sorting of the Laguerre-Gaussian (LG) modes by the radial index using method of higher-order intensity moments. It was shown that when a diaphragm is exposed to such a beam, it causes the birth of a huge number of LG beams with different radial numbers and amplitudes. The information entropy of the states of such a perturbed beam increases sharply.