P. A. Konyaev

Computer simulation of adaptive optics for laser systems in atmospheric applications

Software for computer simulations of adaptive optics systems for atmospheric laser applications designed on the basis of advanced parallel programming techniques is developed. The adaptive optics system model includes the emitting aperture geometry and beam propagation path scenario, vertical profiles of atmospheric parameters, fast parallel split-step Fourier algorithm for solving wave diffraction and propagation equations, time-dependent models of “frozen” atmospheric turbulence with a wide range of scales, and models of the wavefront sensor and controlled deformable mirror. The hardware system for computer simulations is an off-the-shelf desktop with a 6-core 12-thread Intel® Core™ i7-970 CPU at the maximum frequency of 3.5 GHz and an NVIDIA® GeForce GTX 580 graphic accelerator with 512 universal processors operating at 1.5 GHz. Results of simulations of adaptive imaging and laser beam shaping, aimed at estimating the efficiency of adaptive optics systems on atmospheric paths are presented.

Path-averaged differential meter of atmospheric turbulence parameters

A path-averaged differential meter of the structure constant of the atmospheric refractive index, Cn2, has been developed and tested. The results of a model numerical experiment on measuring Cn2 and the horizontal component of average wind velocity transverse to the path are reported.

Adaptive optical system for a ground-based solar telescope

This paper discusses a modified adaptive optical system for a ground-based solar telescope that corrects the influence of the atmosphere and of technical distortions on the quality of the resulting image of the object. An adaptive optical system is developed from traditional optoelectronic systems by incorporating additional elements, namely a wave-front corrector (an active mirror), a device for measuring wave-front distortion (a wave-front sensor), and a reference source that provides an optical signal to set the wave-front sensor. The angular resolution of an image in the telescope can reach diffraction resolution as a result of adaptive correction; i.e., it can be increased by about a factor of 10-25.

Potential capabilities of adaptive-optical systems in the atmosphere

Thermal-blooming correction can reduce high-power laser beam distortions in the atmosphere. We use computer simulations to estimate the efficiency of different phase and amplitude-phase correction algorithms over horizontal and vertical atmospheric paths.

Simultaneous measurements of structure characteristics of atmospheric refraction by optical and acoustic methods

Comparative measurements of the turbulence level were carried out in the surface layer by optical and acoustic methods with the use of equipment designed at Zuev Institute of Atmospheric Optics. The turbulence level in the surface layer was studied at a height of 1.65 m. A stable difference between optical and acoustic data has been found.

Adaptive optics system for solar telescope operating under strong atmospheric turbulence

New results obtained within Russian Science Foundation Project no. 15-19-20013 are presented. The project was started in the middle of 2015 and is aimed at the solution of actual problems of the development of the optoelectronic industry using adaptive optics for astronomy, laser, and other applications. The progress in the development of the up-to-date adaptive optics system for the largest Russian solar telescope, i.e., the 1-m Big Solar Vacuum Telescope of the Baikal Astrophysical Observatory, is described.

Passive optical methods in measurement of the structure parameter of the air refractive index

A passive optical method for estimating the level of atmospheric turbulence (structure parameter of the air refractive index Cn2) from the image jitter is considered. It is proposed to use a high-speed digital video camera and effective two-dimensional parallel algorithms of image processing for measuring Cn2 in real time. Results obtained by the active and passive optical methods, as well as by an acoustic method, are compared.

Studying the astroclimate at Baikal Astrophysical Observatory by optical methods

A technique is proposed for measuring astroclimate characteristics of the Baikal Astrophysical Observatory (BAO) by analysis of the quality of images obtained at a full Sun phase telescope. To estimate the image quality, a modified statistical information “optimal window” algorithm is used. Large amounts of information (thousands of frames) are processed automatically using a hardware-software complex developed at the Institute of Atmospheric Optics based on NVIDIA®CUDA parallel programming technologies and Intel® IPP and MKL libraries. Results of the statistical analysis of solar chromosphere filtergrams in the H-alpha line obtained at BAO during 2001–2002 using a Princeton Instruments 2048B digital camera are presented.

Joint measurements of atmospheric turbulence level with optical and acoustic meters

Complex measurements of atmospheric turbulence level were carried out with the use of a differential turbulence meter, a wavefront sensor, and ultrasonic weather stations. The refractive index structure constant was measured daily along horizontal optical paths at the Basic Experimental Station of the V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. The comparative analysis of the data received is given.

Possibilities for the application of adaptive optics at solar telescopes

Possibilities for the application of adaptive optics at solar telescopes are studied. A modified correlation tracker to measure the image motion at the first focus of the Big Solar Vacuum Telescope (BSVT) at the Baikal Astrophysical Observatory of the Institute for Solar-Terrestrial Physics, the Siberian Branch of the Russian Academy of Sciences, has been investigated experimentally.