@iao.ru
Zuev Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences
Singular optics; optical vortices; singular points of a wavefront; Shack-Hartmann sensor; interference pattern
Scopus Publications
F. Yu. Kanev, V. P. Aksenov, N. A. Makenova, and I. D. Veretekhin
Pleiades Publishing Ltd
Feodor Kanev, Nailya Makenova, and Igor Veretekhin
MDPI AG
This article addresses two issues. Firstly, it was shown that if the initial phase of a Gaussian beam is specified by the sum of Zernike polynomials or by a screen simulating atmospheric turbulence, in the process of propagation, singular points appear in the wavefront of such a beam. With the use of numerical simulation, the dependence of the vortices number on the distortion characteristics and on the distance traveled by the beam was determined. The second problem analyzed in the article is the problem of a phase screen approximation by a series formed by Zernike polynomials. The carried out numerical experiments made it possible to determine the dependence of approximation accuracy on the screen parameters and on the number of polynomials entering the basis of approximation.
Feodor Kanev, Nailia A. Makenova, and Igor Veretekhin
SPIE
In the present article the influence is considered of phase screen characteristics on the statistical properties of dislocations developed in a beam passed this screen. Analysis was performed with application of numerical experiment methods, and in the developed model the screen represented a thin layer of turbulent atmosphere. Special attention was devoted to assessment of the turbulence inner scale impact on distribution of vortices. We have also shown that this distribution meets the requirements of the central limit theorem.
F. Kanev, A. Rukosuev, N. Makenova, and I. Veretekhin
IEEE
Development of singular points in a coherent beam is considered in the paper. The initial phase of radiation was set by Zernike polynomials and by a random phase screen simulating atmospheric turbulence. Several methods of detection were used to register optical vortices.
Feodor Kanev, Nailya A. Makenova, and Igor Veretekhin
SPIE
The objective of current investigation is development of the method intended to extract useful information from a beam in the wavefront of which optical vortices are present. Developed numerical model corresponds approximately to an optical communication system operating in a turbulent atmosphere under conditions of strong distortions of radiation. Specific feature of this system is that information is also transferred by an optical vortex.
F. Yu. Kanev, V. P. Aksenov, N. A. Makenova, and I. D. Veretekhin
Allerton Press
V. P. Lukin, L. V. Antoshkin, L. A. Bolbasova, N. N. Botygina, O. N. Emaleev, F. Yu. Kanev, P. A. Konyaev, E. A. Kopylov, V. V. Lavrinov, L. N. Lavrinova,et al.
Pleiades Publishing Ltd
Abstract A survey of the development of adaptive optics, its methods, and tools for the elimination of irregular distortions appearing in the process of light propagation in an inhomogeneous medium is presented. Many ideas developed in recent years were put forward rather long ago; however, only now, owing to creation of state-of-the-art hardware components of optoelectronic systems and devices, they begin to be included in the widest fields of science and technology. The work also presents the current status of adaptive optics systems in solar astronomy, as well as some aspects of their use in systems correcting distortions of powerful laser systems. A retrospective analysis of investigations in the V.E. Zuev Institute of Atmospheric Optics in relation to adaptive optics is carried out.
Feodor Kanev, Valerii Aksenov Aksenov, Nailia A. Makenova, and Igor Veretekhin Veretekhin
SPIE
Properties of vortex radiation are discussed in the article using the data obtained by the authors and information found in references. Possible applications of such radiation are considered. Special attention is devoted to the methods of vortex registration. Precision of two registration algorithms is compared and particularities of their practical realization are analyzed.
F. Yu. Kanev, N. A. Makenova, V. P. Lukin, O. L. Antipov, and I. D. Veretekhin
Pleiades Publishing Ltd
Results of the simulation of multichannel radiation propagation under conditions of thermal blooming are presented. The correction of nonlinear thermal distortion by means of the beam phase and amplitudephase control is considered. The results show the dependence of the correction effectiveness on the number of channels and on the precision of the reference beam phase retrieval. An additional increase in the effectiveness is possible by means of adjustment of amplification in the channels of the optical system, i.e., with the use of amplitude-phase control over the beam wavefront.
Nailia A. Makenova, Feodor Kanev, Valerii Aksenov, Igor Veretekhin, Feodor Starikov, Yurii Dolgopolov, and Aleksander Kopalkin
SPIE
The algorithm of an optical vortex coordinates and topological charge detection is considered. In the algorithm a vortex is localized as a point of an interference fringe branching. With application of the algorithm interference patterns obtained in laboratory and numerical experiments are analyzed and characteristics of vortices revealed in corresponding examples are presented.
Feodor Y. Kanev, I. D. Veretekhin, Nailia A. Makenova, and Vladimir P. Lukin
SPIE
In this paper the results of simulation are presented of multichannel radiation propagation in a turbulent atmosphere and under conditions of thermal blooming, and correction for nonlinear thermal distortion on the base of the beam phase control is considered. The results demonstrate dependence of correction effectiveness on number of channels and on precision of a reference beam phase reconstruction. Addition increase of effectiveness is possible with adjustment of amplification in the channels of the optical system, i.e., with the use of amplitude-phase control of radiation.
O. L. Antipov, F. Yu. Kanev, V. P. Lukin, and N. A. Makenova
Pleiades Publishing Ltd
Numerical experimental results characterizing the propagation of multichannel laser radiation in the atmosphere are presented and the possibility of compensating turbulent distortions by use of phase control is considered. It is shown that the effectiveness of adaptive correction depends on the number of channels in the system and on the accuracy of the reference radiation phase reconstruction. The effectiveness can be additionally increased by gain control in each of the channels, i.e., by passing to amplitude-phase control.
Nailia A. Makenova, Feodor Kanev, Vladimir Lukin, Oleg Antipov, and I. D. Veretekhin
SPIE
In this paper the results of simulation are presented of multichannel radiation propagation under conditions of thermal blooming, and correction for nonlinear thermal distortion on the base of the beam phase control is considered. The results demonstrate dependence of correction effectiveness on number of channels and on precision of a reference beam phase reconstruction. Addition increase of effectiveness is possible with adjustment of amplification in the channels of the optical system, i.e., with the use of amplitude-phase control of radiation..
F Kanev, N Makenova, R Nesterov, and I Izmailov
IOP Publishing
A mathematical model of an adaptive optics system was described in the article. The model included two main components: the model of an adaptive mirror and model of beam propagation under conditions of thermal blooming. Results of numerical simulation of adaptive optics systems were compared with data of laboratory experiments. High reliability of the model was shown.
F. Yu. Kanev, V. P. Lukin, N. A. Makenova, O. L. Antipov, and Halil Tanyer Eyyuboğlu
SPIE
In this paper the results of simulation are presented of multichannel radiation propagation in the atmosphere, and correction for turbulent distortion on the base of the beam phase control is considered. The results demonstrate dependence of correction effectiveness on number of channels and on precision of a reference beam phase reconstruction. Additionally increase of effectiveness is possible with adjustment of amplification in the channels of the optical system, i.e., with the use of amplitude-phase control of radiation.
O. L. Antipov, F. Yu. Kanev, N. A. Makenova, V. P. Lukin, and E. I. Tsyro
Allerton Press
This paper presents the results of modeling the propagation of multichannel radiation under free diffraction conditions and discusses features inherent in this type of beams under these conditions. In addition, the effect of distortions arising in a turbulent atmosphere on radiation quality is considered, and the efficiency of adaptive compensation of atmospheric turbulence is analyzed.
Oleg Antopov, Feodor Kanev, Nailia Makenova, and Vladimir Lukin
SPIE
The results of numeric simulation are presented in the paper of multichannel laser radiation propagation under conditions of free diffraction and in a turbulent atmosphere. It was shown that in free space a multichannel system allows one to obtain higher concentration (20-50%) of radiation energy on the object comparing with a Gaussian beam. Intensity of atmospheric distortion decreases with increase of the number of channels. Adaptive correction for turbulent distortions results in two-times increase of energy concentration for systems with 9 and 81 channels. For systems with greater number of channels (201 channels) the results of correction do not depend on turbulence intensity.
F.Yu. Kanev, N.A. Makenova, E.G. Gorynova, and O.L. Antipov
IEEE
Generation of high-power laser radiation is frequently performed with the use of multichannel optical systems with coherently-combined channels. Channels usually include amplifiers and phase control units phase shifts in which are obtained with optic-electric effects, nonlinear optical interaction of radiation, or with piezoelements. In the paper the results of simulation are presented of multichannel laser radiation propagation under conditions of free diffraction. Influence of distortions developed in channels on effectiveness of energy transfer is also considered. It was shown that with increase of channel number the influence of random tilts and piston-type aberration decreased.
Oleg Antopov, Feodor Kanev, Nailia A. Makenova, and Ekaterina Tsyro
SPIE
In the paper the results of simulation are presented of multichannel laser radiation propagation under conditions of free diffraction. Influence of distortions developed in channels on effectiveness of energy transfer is also considered. It was shown that with increase of channel number the influence of random tilts and piston-type aberration decreased.
Feodor Kanev, Natalya Atepaeva, Vladimir Lukin, and Nailya Makenova
SPIE
In the present paper efficiency of adaptive correction is analyzed in the turbulent atmosphere and under the conditions of thermal blooming. A numerical model of a typical adaptive optics system was developed to carry out the investigations. As it is known, phase conjugation and multidither, i.e., the algorithms commonly employed to correct for thermal and turbulent distortions of laser beams are unstable in nonlinear medium. We demonstrated that stability of phase control is possible to increase introducing the modifications of the algorithms. Also we demonstrated that phase compensation does not insure complete correction for thermal or turbulent aberrations induced by an atmospheric layer. To correct for aberrations under these conditions it is possible to employ amplitude-phase control over the beam, for example, to use the wavefront reversal algorithm. Realization of the algorithm is possible in a two-mirror adaptive system in which the control over beam phase is performed in two planes at the access to the medium. In numerical experiments it was shown that the two-mirror system insures the absolute compensation for a thin turbulent layer placed at arbitrary distance from the aperture of a laser source and high effectiveness of compensation for distributed lens comparing with phase-only algorithms.
V. Lukin, F. Kanev, and N. Makenova
SPIE
A general model of a typical adaptive optics system is described in the report. The model includes all main elements of a real system: the path of a beam propagating in the atmosphere, wavefront sensor, and adaptive mirror with continuous surface. Solution to the some of adaptive optics problems was obtained with the model. These results were included in the report as illustration ofthe model utility.
Feodor Y. Kanev, Vladimir V. Lukin, and Nailya A. Makenova
SPIE
A numerical model of a typical adaptive optics system is described in the report. The developed computer application corresponding to the model includes all the main elements of a real system, namely, computer codes simulating radiation propagation in a turbulent atmosphere with thermal blooming and codes simulating the elements of adaptive optics system (a model of a Shack-Hartmann wavefront sensor, two algorithms of dislocation localization, and a model of adaptive mirror with continuous surface). In the report we include solutions to the some of adaptive optics problems obtained with the model: realization of amplitude-phase control in two-mirror adaptive system, the method to improve the stability of correction for thermal blooming, evaluation of a Shack-Hartmann sensor performance, and some others. These results demonstrate that the set of the developed models is a powerful tool for simulations in the field of adaptive optics.
Feodor Y. Kanev, Nailya Makenova, and Vladimir P. Lukin
SPIE
There are exists several sources of errors in an adaptive optics system. The main source associated with the violation of the optical reciprocity principle in algorithm of phase conjugation, namely, with substitute of beacon amplitude distribution by distribution of a Gaussian beam generated by a laser. Absolute correction of turbulent aberration is possible only in case of strict maintenance of a reciprocity principle, i.e. in case of phase reversal algorithm application. In paper the possibility is considered to realize phase reversal algorithm in a linear system with the use of phase control of the beam. The system should include two mirrors separated by the vacuum gap of a finite size. Comparison of efficiency of correction on the base of phase conjugation and with the use of two mirror adaptive system were obtained.
Feodor Y. Kanev, Vladimir P. Lukin, and Nailya A. Makenova
SPIE
This paper considers the problem of forming a preset surface of a segmented mirror of a telescope. An iteration algorithm based on analysis of the interference pattern of the radiation reflected from the mirror is used for phasing the mirror segments. At every iteration, the current interferogram is compared with the reference one obtained for the surface of a preset shape. The value of the control goal function, whose minimum is determined in the algorithm, decreases with the decreasing discrepancy between the interferograms. This technique provides for formationof a plane-reflecting surface of the mirror, if the relative displacement of segments does not exceed the half wavelength. It is shown that to extend the range of acceptable displacements, it is necessary to introduce additional sources of radiation of specially chosen wavelengths. In such a case, the dynamic range of the algorithm can be extended up to 30 μm.