Grigory Yakopov

Russian Academy of Sciences | RAS · OPTICAL DIVISIONS

Superconducting undulators (SCUs) can offer a much higher on-axis undulator field than state-of-the-art cryogenic permanent-magnet undulators with the same period and vacuum gap. The development of shorter-period and high-field SCUs would allow the free-electron laser and synchrotron radiation source community to reduce both the length of undulator...

This article presents the results of evaluating the possibility of conducting radio astronomy studies in the windows of atmospheric transparency ~100, ~230, and ~350 GHz using the optical Big Telescope Alt-Azimuthal (BTA) of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). A list of some promising astronomical tas...

The implementation and further improvements of superconducting undulators are part of the European XFEL facility development program. Within this program, a magnetic field test facility is being developed. Named SUNDAE2 (Superconducting UNDulAtor Experiment 2), it aims to perform in-vacuum magnetic field measurements of superconducting undulators (...

The article presents the results of evaluating the possibility of conducting radio astronomy studies in the windows of atmospheric transparency ~100, ~230 and ~350 GHz using the optical Big Telescope Alt-Azimuthal (BTA) of the SAO RAS. A list of some promising astronomical tasks is proposed. The astroclimat conditions at the BTA site and possible o...

For more than 5 years, superconducting undulators (SCUs) have been successfully delivering X-rays in storage rings. The European X-Ray Free-Electron Laser Facility (XFEL) plans to demonstrate the operation of SCUs in X-ray free-electron lasers (FELs). For the same geometry, SCUs can reach a higher peak field on the axis with respect to all other av...

An overview of different arrays of electrically small annular antennas of 350 GHz band with integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) detectors is presented in this paper. Arrays developed for both astronomical observations on the BTA 6 m telescope and measurements there of test sources for investigation of a...

Superconductor–insulator–normal metal–insulator–superconductor (SINIS) detectors are developed with promising applications in two scheduled instruments of the space project of the Millimetron radio telescope, as well as ground-based high-altitude BTA (Big Telescope Alt-Azimuthal) and Suffa telescopes. For the multipixel imaging array, two matrix ve...

We give a review of both our own original scientific results of the development of superconducting receivers for sub-terahertz astronomy and the main leading concepts of the global instrumentation. The analysis of current astronomical problems, the results of microwave astroclimate research, and the development of equipment for sub-terahertz radio...

An overview of different arrays of electrically small annular antennas of 350 GHz band with integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) detectors is presented in this paper. Arrays developed for both astronomical observations on the BTA 6 m reflector and measurements there of test sources for investigation of a...

A superconductor-insulator-normal metal-insulator-superconductor (SINIS) detector integrated in a planar 90 GHz band twin-slot antenna with a 2 GHz superconducting resonator readout was fabricated and experimentally studied. In order to achieve high pixel count, the traditional dc readout of the SINIS detector is replaced by NbN coplanar 13.850 mm...

Отмечены устройства и функции спектрографа высокого разрешения 6-метрового телескопа БТА, охваченные программой улучшения параметров прибора. Программа выполняется по плану УНУ и плану развития средств наземной поддержки проекта «Спектр-УФ». The devices and functions of the high-resolution spectrograph of the 6-meter BTA telescope covered by the pr...

Сообщается о завершении очередного этапа работ по созданию эшелле-спектрографа ESPriF, предназначенного для спектроскопии и спектрополяриметрии звезд и планетарных туманностей. Потенциальное качество нового спектрографа оценивается относительно характеристик Основного звездного спектрографа (ОЗСП) БТА, используемого сегодня для обеспечения большей...

New challenges in submillimeter wave astronomy require instruments with a combination of high sensitivity and angular resolution, wide field of view and multiwave (multicolor) spectral range. New large single mm/submm telescopes are in high demand, as well as their inclusion in the global Event Horizon Telescope (EHT) VLBI network. At the same time...

We report the results of laboratory tests of the first version of the high-resolution fiber-fed spectrograph designed for the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). During laboratory tests a spectral resolution of about 70 000 was achieved. The peak efficiency of the entire optical path of the spectrograph (...

For improving the dynamic range and sensitivity at high power load we have integrated Superconductor-Insulator-Normal metal-Insulator-Superconductor (SINIS) bolometers with a Frequency Selective Surface (FSS) based distributed absorber formed by a series and parallel array consisting of 25 annular antenna elements, each containing two SINIS bolomet...

We fabricated and experimentally studied a wideband metamaterial comprising a 2D-array of annular antennas with Superconductor-Insulator-Normal metal-Insulator-Superconductor (SINIS) bolometers. The Annular Antenna Array Metamaterial (AAAM) was designed for a frequency range of 300-450 GHz and consists of periodically arranged electrically small ri...

The results of measurements of astroclimate characteristics in the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO, North Caucasus) in 2012 and 2016 are presented. The experimental results are obtained from long-term observation series of the day and night astroclimate in the SAO. The presence of non-Kolmogorov coherent tu...

The types of astronomical-spectrum calibrations in the wavelengths used in spectroscopy of stars at the 6-m BTA optical telescope are listed. A device has been developed for simultaneous recording of a star spectrum and a reference emission spectrum.

Series and parallel arrays of annular antennas optimized for 350 GHz frequency band with SINIS (Superconductor - Insulator - Normal metal - Insula-tor-Superconductor) bolometers and cryogenically cooled receivers for series of modern SubTHz ob-servatories have been designed, fabricated and stud-ied. The detectors are matched to incoming beam by an...

We have investigated the optical and spectral response of a 350 GHz receiver made of annular antenna array with SINIS bolometer elements. Receiver is intended for using at Big Alt-Azimuthal Telescope (BTA). Samples were measured in a dilution cryostat at temperatures in the range 80-400 mK. Voltage responsivity approaches 3*1e9 V/W. Spectral bandwi...

We designed a cross-dispersion fiber-fed spectrograph for moderate-diameter telescopes. The instrument can simultaneously record the wavelength interval spanning from 3850 to 10 850 Å at a spectral resolution of R = 45 000 with the maximum diameter of the input star image of \(3''_ \cdot 3\) . The instrument allows the spectrum of the star to be re...

We report on the development of the medium-resolution spectrophotometer to accompany (in real time) spectral observations performed with the high resolution spectrographs on the 6-m telescope BTA.

A base model of the high-resolution fiber-fed spectrograph is developed. In combination with the SAO 1-meter telescope the spectrograph has the following parameters: spectral resolution R=45000, the number of simultaneous registered orders is 86 within spectral region 3850$\div$10850 \AA{}, echelle orders are overlapping for $\lambda <9000$ \AA{}.

Problems of automated hartmanogramm processing while controlling optical systems using Hartmann technique are considered. Examined a separation phase and shown algorithms elaborated for locating the spots.

A dilution microcryostat is described, which is designed for conducting physical measurements at temperatures down to 0.1 K or lower. A refrigerator with an impulse tube is used to provide its operation. Owing to the use of a passive stabilization system, which is based on helium condensation, the temperature can be maintained at a level of 0.1 K f...

We describe design of two-polarization imaging array of 7 antenna-coupled TES-bolometers. The fabrication procedure involves both electron beam lithography and convenient optical lithography resulting in submicron definition of TES absorber films (down to ~ 0.2 μm) integrated within planar submm-wave antenna. Concept of matching optics between t...

We are developing the high sensitive 0.13- 0.38 THz radiometer for 6 m optical telescope BTA of SAO RAS with the purpose to add frequency operation points in corresponding atmosphere transparency windows to already existing operation frequencies in observation facilities of the Observatory from ultraviolet region - 3000 Angstroms at BTA till maximu...

We develop a high-sensitivity matrix radiometer which will be used on the large altazimuth telescope BTA of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences (Fig. 1) for performing astronomical observations in atmospheric transparency windows in the poorly explored frequency range from 0.13 to 0.38 THz (wavelengths fro...

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