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Elezov, M. S., Scherbatenko, M. L., Sych, D. V., & Goltsman, G. N. (2018). Active and passive phase stabilization for the all-fiber Michelson interferometer. In J. Phys.: Conf. Ser. (Vol. 1124, 051014 (1 to 5)).
Abstract: We put forward two methods for phase stabilization in the all-fiber Michelson interferometer. To perform passive phase stabilization, we use a heat bath for all fibers and electro-optical components, and put the interferometer in a hermetic case. To perform active phase stabilization, we monitor output power of the interferometer and develop an electronic feedback control. The phase stabilization methods enable stable interference pattern for several minutes, and can be helpful for the development of the optimal quantum receiver for coherent signals.
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Finkel, M., Thierschmann, H. R., Galatro, L., Katan, A. J., Thoen, D. J., de Visser, P. J., et al. (2016). Branchline and directional THz coupler based on PECVD SiNx-technology. In 41st IRMMW-THz.
Abstract: A fabrication technology to realize THz microstrip lines and passive circuit components is developed and tested making use of a plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNx) dielectric membrane. We use 2 μm thick SiNx and 300 nm thick gold layers on sapphire substrates. We fabricate a set of structures for thru-reflect-line (TRL) calibration, with the reflection standard implemented as a short through the via. We find losses of 9.5 dB/mm at 300 GHz for a 50 Ohm line. For a branchline coupler we measure 2.5 dB insertion loss, 1 dB amplitude imbalance and 21 dB isolation. Good control over the THz lines parameters is proven by similar performance of a set of 5 structures. The directional couplers show -14 dB transmission to the coupled port, -24 dB to the isolated port and -25 dB in reflection. The SiNx membrane, used as a dielectric, is compatible with atomic force microscopy (AFM) cantilevers allowing the application of this technology to the development of a THz near-field microscope.
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Shcherbatenko, M., Lobanov, Y., Finkel, M., Maslennikov, S., Pentin, I., Semenov, A., et al. (2014). Development of a 30 THz heterodyne receiver based on a hot-electron-bolometer mixer. In Proc. 25th Int. Symp. Space Terahertz Technol. (122).
Abstract: We present new Hot-Electron-Bolometer (HEB) mixers designed for mid-IR spectroscopy targeting astrophysical and geophysical observations where high sensitivity and spectral resolution are required. The mixers are made of an ultrathin NbN film deposited on GaAs substrates. Two entirely different types of the devices have been fabricated. The first type is based on a direct radiation coupling concept and the mixing devices are shaped as squares of 5×5 μm 2 (which corresponds to the diffraction limit at the chosen wavelength) and 10×10 μm 2 (which was used to establish a possible influence of the contact pads on the radiation absorption). The second type utilizes a spiral antenna designed with HFSS. The fabrication and layout of the devices as well as the performance comparison will be presented. During the experiments, the HEB mixer was installed on the cold plate of a LHe cryostat. A germanium window and an extended semi-spherical germanium lens are used to couple the radiation. The cryostat is equipped with a germanium optical filter of thickness 0.5 mm and with a center wavelength of 10.6 mμ. The incident power absorption is measured by using the isothermal method. As a Local Oscillator, a 10.6 micrometers line of a CO2 gas laser is used. We further characterize the frequency response of the spiral antenna with a FIR-spectrometer. The noise characteristics of the mixers are determined from a room temperature cold load and a heated black body at ~600 K as a hot load.
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Семенов, А. В., Корнеев, А. А., Лобанов, Ю. В., Корнеева, Ю. П., Рябчун, С. А., Третьяков, И. В., et al. (2012). Оценка поляризационных искажений, вносимых оптической системой радиотелескопа миллиметрового диапазона. Преподаватель ХХI век, (4), 230–236.
Abstract: В статье рассмотрена поляризация электромагнитного поля вблизи фокальной точки телескопической системы. Оценена верхняя граница поляризационных искажений, вносимых отражающими поверхностями, в том числе с учетом неидеальности отражения.
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Wild, W., Baryshev, A., de Graauw, T., Kardashev, N., Likhachev, S., Goltsman, G., et al. (2008). Instrumentation for Millimetron – a large space antenna for THz astronomy. In Proc. 19th Int. Symp. Space Terahertz Technol. (pp. 186–191).
Abstract: Millimetron is a Russian-led 12m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation and funded for launch after 2015. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron is currently in a conceptual design phase carried out by the Astro Space Center in Moscow and SRON Netherlands Institute for Space Research. It will use a passively cooled deployable antenna with a high-precision central 3.5m diameter mirror and high- precision antenna petals. The antenna is specified for observations up to ~2 THz over the whole 12m diameter, and to higher frequencies using the central 3.5m solid mirror. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space VLBI system. As single-dish, angular resolutions on the order of 3 to 12 arcsec will be achieved and spectral resolutions of up to 10 6 employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines resulting in micro-arcsec angular resolution. The scientific payload will consist of heterodyne and direct detection instruments covering the most important sub-/millimeter spectral regions (including some ALMA bands) and will build on the Herschel and ALMA heritage.
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