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Author Smirnov, A.; Golubev, E.; Arkhipov, M.; Filina, E.; Pyshnov, V.; Myshonkova, N.; Fedorchuk, S.; Kosmovich, T.; Vinogradov, I.; Baryshev, A.; de Graauw, Th.; Likhachev, S.; Kardashev, N. openurl 
  Title Millimetron Space Observatory: progress in the development of payload module Type Conference Article
  Year 2019 Publication Proc. 30th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 30th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages (down) 180-181  
  Keywords Millimetron space observatory, primary mirror  
  Abstract Millimetron Space Observatory (MSO) is mission addressed to creation a space cryogenic telescope with aperture about 10-m [1]. Such telescope will allow scientific community to have an astronomical instrument with enormous sensitivity and angular resolution in the submillimeter and far-infrared wavelength ranges. We plan to install at the telescope several FIR and sub-millimeter scientific instruments, which will enable high-resolution imaging and spectroscopy observations with unprecedented sensitivity. At the same time, MSO will enable observations with an extremely high angular resolution (up to 0.1×10 -6 arcsec) as an element of a ground-space very long baseline interferometry system (S-VLBI). Thereby the observatory will contribute breakthrough capability into solution a number of cosmology and fundamental astrophysics questions about the origin and evolution of our Universe, galaxies, stars and other objects [2]. The MSO is divided into two parts: the payload module and the bus module. Due to the complexity of the payload module, most of the recent years of work are focused on it. This module includes an antenna of the telescope, scientific receivers, functional and service systems and a high-gain radio system for transmitting scientific data to Earth. The primary mirror of the telescope will be deployable and consist from of a 3-m aperture central part surrounded by 24 deployable petals. The concept of petals deployment is based on the successfully launched and currently working Radioastron project [3]. The surface accuracy of the deployable 10-m primary mirror of Radioastron achieves about 1 mm in space conditions. The telescope of MSO would have much better surface accuracy – less than 10 μm (rms). In order to achieve this we plan to use an active surface control system based on a wave front sensing. This system will be periodically employed to correct inaccuracies in the positions of the panels caused by different factors. A combination of a high modulus carbon fiber reinforced plastic (CFRP) and a cyanate ester resin as a binder provides a lightweight structure with low moisture absorption, high thermal stability and high stiffness. This combination has been chosen for the material of the primary mirror of telescope and many parts of it. The panels are mounted on the back support structure (Fig. 1) made from CFRP via precision cryogenic actuators. To achieve the required sensitivity of the telescope in the submm/FIR we need to cool antenna down to the temperature less than 10K (goal). It may be possible to do this on-orbit only by a combination of effective radiation cooling and additional active mechanical cooling. A cold space antenna requires minimization and stability of external thermal radiation. This is one of the reasons why MSO will be placed into orbit around the second Earth-Sun Lagrange point (L2). The MSO antenna into L2 will be cooled passively to a temperature about 30 – 60K by a suite of the deployable multi-layer V-groove shields. The following steps to reduce the temperature of the antenna are based on active reducing the thermal loads applied to it. Active mechanical cooling is based on existing close cycling space mechanical coolers. In this work, we will focus on the progress in the development of payload module.  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1280  
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Author Tovpeko, N. A.; Trifonov, A. V.; Semenov, A. V.; Antipov, S. V.; Kaurova, N. S.; Titova, N. A.; Goltsman, G. N. url  openurl
  Title Bandwidth performance of a THz normal metal TiN bolometer-mixer Type Conference Article
  Year 2019 Publication Proc. 30th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 30th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages (down) 102-103  
  Keywords TiN normal metal bolometer, NMB  
  Abstract We report on the bandwidth performance of the normal metal TiN bolometer-mixer on top of an Al 2 O 3 substrate, which is capable to operate in a wide range of bath temperatures from 77 K – 300 K. The choice of the combination TiN / Al 2 O 3 is related to an advanced heat transport between the film and the substrate in this pair and the sufficient temperature coefficient of resistance. The data were taken at 132.5 – 145.5 GHz with two BWOs as a signal and an LO source. Measurements were taken on TiN films of different thickness starting from 20 nm down to 5 nm coupled into a spiral Au antenna, which improves matching of incoming radiation with the thin TiN fim. Our experiments demonstrate effective heat coupling from a TiN thin film to an Al 2 O 3 substrate (111) boosting gain bandwidth (GB) of TiN bolometer up to 6 GHz for 5 nm thin film. Current results indicate weak temperature dependence of GB on the bath temperature of the TiN bolometer. Theoretical estimations of GB performance meet with experimental data for 5 nm thin TiN films.  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1279  
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Author Nikogosyan, A. S.; Martirosyan, R. M.; Hakhoumian, A. A.; Makaryan, A. H.; Tadevosyan, V. R.; Goltsman, G. N.; Antipov, S. V. url  doi
openurl 
  Title Effect of absorption on the efficiency of terahertz radiation generation in the metal waveguide partially filled with nonlinear crystal LiNbO3, DAST or ZnTe Type Journal Article
  Year 2019 Publication J. Contemp. Phys. Abbreviated Journal J. Contemp. Phys.  
  Volume 54 Issue 1 Pages (down) 97-104  
  Keywords nonlinear crystal, THz, waveguide  
  Abstract The influence of terahertz (THz) radiation absorption on the efficiency of generation of coherent THz radiation in the system ‘nonlinear-optical crystal partially filling the cross section of a rectangular metal waveguide’ has been investigated. The efficiency of the nonlinear frequency conversion of optical laser radiation to the THz range depends on the loss in the system and the fulfillment of the phase-matching (FM) condition in a nonlinear crystal. The method of partially filling of a metal waveguide with a nonlinear optical crystal is used to ensure phase matching. The phase matching is achieved by numerical determination of the thickness of the nonlinear crystal, that is the degree of partial filling of the waveguide. The attenuation of THz radiation caused by losses both in the metal walls of the waveguide and in the crystal was studied, taking into account the dimension of the cross section of the waveguide, the degree of partial filling, and the dielectric constant of the crystal. It is shown that the partial filling of the waveguide with a nonlinear crystal results in an increase in the efficiency of generation of THz radiation by an order of magnitude, owing to the decrease in absorption.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1068-3372 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1289  
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Author Tiulina, V.; Iomdina, E.; Goltsman, G.; Seliverstov, S.; Sianosyan, A.; Teplyakova, K.; Rusova, A.; Zaitsev, S.; Zernii, E.; Senin, I. url  doi
openurl 
  Title UVB promotes the initiation of uveitic inflammatory and changes in thehydration of the cornea in vivo Type Miscellaneous
  Year 2019 Publication FEBS Open Bio Abbreviated Journal FEBS Open Bio  
  Volume 9 Issue S1 Pages (down) 79  
  Keywords medicine; scheimpflug imaging; UVB; confocal microscopy; cornea; optical coherent tomography; rabbit eyes; terahertz radiation  
  Abstract Recently, active research has been conducted in the field of terahertz (THz) scanning of human tissues for non­invasive determination of their hydration level, which haves hown high diagnostic efficiency of this technology in various pathological conditions. Recently, we have developed a laboratory model of the facility for monitoring the state of the water balance of the cornea using THz scanning in vivo, which opens up the possibility of applying this approach in ophthalmology. The aim of the work wasto compare the results of the THz scan of the cornea with its clinical changes using the example of an experimental model of the UV­ induced keratouveitis. Anexperimental study, which included a comprehensive assessment of clinical changes in the cornea of rabbits during keratouveitis induction, revealed a decrease in the stability of the tear film, pathological changes in the corneal epithelium and stroma, as well as its anatomical and optical parameters. Comparison of data obtained in the THz scan of the cornea with tears production, optical coherence tomography and confocal microscopy showed their consistency in all observation periods, which allows us to conclude that the developed laboratory setup works and the feasibility of further research to promote the corneal hydration evaluation technology in clinical practice. Acknowledgements: Research was funded by the RSF, grant number 16­15­00255.  
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  Series Volume Series Issue Edition  
  ISSN 2211-5463 ISBN Medium  
  Area Expedition Conference  
  Notes Poster P-01-040 Approved no  
  Call Number Serial 1276  
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Author Kovaluyk, V.; Lazarenko, P.; Kozyukhin, S.; An, P.; Prokhodtsov, A.; Goltsman, G.; Sherchenkov, A. url  openurl
  Title Influence of the phase state of Ge2Sb2Te5 thin cover on the parameters of the optical waveguide structures Type Abstract
  Year 2019 Publication Proc. Amorphous and Nanostructured Chalcogenides Abbreviated Journal Proc. Amorphous and Nanostructured Chalcogenides  
  Volume Issue Pages (down) 47-48  
  Keywords optical waveguides  
  Abstract The fast switching time of Ge-Sb-Te thin films between amorphous and crystalline states initiated by laser beam as well as significant change of their optical properties and the preservation of metastable states for tens of years open wide perspectives for the application of these materials to fully optical devices [1], including high-speed optical memory [2]. Here we study optical properties of the Ge2Sb2Te5 (GST225) thin films integrated with on-chip silicon nitride O-ring resonator. The rib waveguide of the resonator was formed the first stage of e-beam lithography and subsequent reactive-ion etching. We used the second stage of e-beam lithography combining with lift-off method for the formation of GST225 active region on the resonator ring surface. The amorphous GST225 thin films were prepared by magnetron sputtering, and were capped by thin silicon oxide on their tops. The length of the GST225 active region varied from 0.1 to 20 μ m. Crystallization of amorphous thin films was carried out at the temperature of 400 °C for 30 minutes. Auger electron spectroscopy and transmission electron microscopy were used for studying composition and structure of investigated GST225thin films, respectively. It was observed that crystallization of amorphous GST225 film lead to a decrease of the optical power, transmitted through the waveguide. Comparison of the optical transmittance of O-ring resonators before and after the GST225 deposition allowed to identify the change in the Q-factor and the wavelength peak shift. This can be explained by the differences of the complex refractive indexes of GST225 thin films in the amorphous and crystalline states. From the measurement data, the GST225 effective refractive index was extracted depending on the ring waveguide width of the resonator for a telecommunication wavelength of 1550 nm.  
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  Publisher Technical University of Moldova Place of Publication Editor  
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  Area Expedition Conference  
  Notes Poster Approved no  
  Call Number Serial 1281  
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Author Goltsman, G. url  openurl
  Title Quantum-photonic integrated circuits Type Conference Article
  Year 2019 Publication Proc. IWQO Abbreviated Journal Proc. IWQO  
  Volume Issue Pages (down) 22-23  
  Keywords WSSPD, waveguide SSPD, SNSPD, quantum optics, integrated optics, superconducting nanowire single-photon detector  
  Abstract We show the design, a history of development as well as the most successful and promising approaches for QPICs realization based on hybrid nanophotonic-superconducting devices, where one of the key elements of such a circuit is a waveguide integrated superconducting single-photon detector (WSSPD). The potential of integration with fluorescent molecules is discussed also.  
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  Notes Approved no  
  Call Number Serial 1287  
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Author Moshkova, M.; Divochiy, A.; Morozov, P.; Vakhtomin, Y.; Antipov, A.; Zolotov, P.; Seleznev, V.; Ahmetov, M.; Smirnov, K. url  doi
openurl 
  Title High-performance superconducting photon-number-resolving detectors with 86% system efficiency at telecom range Type Journal Article
  Year 2019 Publication J. Opt. Soc. Am. B Abbreviated Journal J. Opt. Soc. Am. B  
  Volume 36 Issue 3 Pages (down) B20  
  Keywords NbN PNR SSPD, SNSPD  
  Abstract The use of improved fabrication technology, highly disordered NbN thin films, and intertwined section topology makes it possible to create high-performance photon-number-resolving superconducting single-photon detectors (PNR SSPDs) that are comparable to conventional single-element SSPDs at the telecom range. The developed four-section PNR SSPD has simultaneously an 86±3% system detection efficiency, 35 cps dark count rate, ∼2 ns dead time, and maximum 90 ps jitter. An investigation of the PNR SSPD’s detection efficiency for multiphoton events shows good uniformity across sections. As a result, such a PNR SSPD is a good candidate for retrieving the photon statistics for light sources and quantum key distribution systems.  
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  ISSN 0740-3224 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1225  
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Author Bandurin, Denis; Svintsov, Dmitry; Gayduchenko, Igor; Xu, Shuigang; Principi, Alessandro; Moskotin, Maksim; Tretyakov, Ivan; Yagodkin, Denis; Zhukov, Sergey; Taniguchi, Takashi; Watanabe, Kenji; Grigorieva, Irina; Polini, Marco; Goltsman, Gregory; Geim, Andre; Fedorov, Georgy url  openurl
  Title Resonant terahertz photoresponse and superlattice plasmons in graphene field-effect transistors Type Abstract
  Year 2019 Publication APS March Meeting Abbreviated Journal APS March Meeting  
  Volume Issue Pages (down) F14.015  
  Keywords  
  Abstract Plasmons, collective oscillations of electron systems, can couple light and electric current, and thus can be used to create compact photodetectors, radiation mixers, and spectrometers. Despite the effort, it has proven challenging to implement plasmonic devices operating at THz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically-tunable plasmons. In this talk, we will demonstrate plasmon-assisted resonant detection of THz radiation by antenna-coupled graphene FETs that act as both rectifying elements and plasmonic Fabry-Perot cavities amplifying the photoresponse. We will show that by varying the plasmon velocity using gate voltage, our detectors can be tuned between multiple resonant modes, a functionality that we apply to measure plasmons' wavelength and lifetime in graphene as well as to probe collective modes in its moire minibands. Our approach offers a convenient tool for further plasmonic research that is often difficult under non-ambient conditions and promises a viable route for various THz applications. We acknowledge Leverhulme Trust, Russian Science Foundation Grants N18-72-00234 and 17-72-30036, Russian Foundation for Basic Research No. 18-57-06001 and 16-29-03402.  
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  Notes Approved no  
  Call Number Serial 1290  
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Author Chandrasekar, R.; Lapin, Z. J.; Nichols, A. S.; Braun, R. M.; Fountain, A. W. url  doi
openurl 
  Title Photonic integrated circuits for Department of Defense-relevant chemical and biological sensing applications: state-of-the-art and future outlooks Type Conference Article
  Year 2019 Publication Opt. Eng. Abbreviated Journal Opt. Eng.  
  Volume 58 Issue 02 Pages (down) 1  
  Keywords photonic integrated circuits, PIC, optical waveguides, defense applications  
  Abstract Photonic integrated circuits (PICs), the optical counterpart of traditional electronic integrated circuits, are paving the way toward truly portable and highly accurate biochemical sensors for Department of Defense (DoD)-relevant applications. We introduce the fundamentals of PIC-based biochemical sensing and describe common PIC sensor architectures developed to-date for single-identification and spectroscopic sensor classes. We discuss DoD investments in PIC research and summarize current challenges. We also provide future research directions likely required to realize widespread application of PIC-based biochemical sensors. These research directions include materials research to optimize sensor components for multiplexed sensing; engineering improvements to enhance the practicality of PIC-based devices for field use; and the use of synthetic biology techniques to design new selective receptors for chemical and biological agents.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0091-3286 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1346  
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Author Polyakova, M.; Semenov, A. V.; Kovalyuk, V.; Ferrari, S.; Pernice, W. H. P.; Gol'tsman, G. N. url  doi
openurl 
  Title Protocol of measuring hot-spot correlation length for SNSPDs with near-unity detection efficiency Type Journal Article
  Year 2019 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 29 Issue 5 Pages (down) 1-5  
  Keywords SSPD, waveguide-integrated SNSPD, hot-spot interaction length  
  Abstract We present a simple quantum detector tomography protocol, which allows, without ambiguities, to measure the two-spot detection efficiency and extract the hot-spot interaction length of superconducting nanowire single photon detectors (SNSPDs) with unity intrinsic detection efficiency. We identify a significant parasitic contribution to the measured two-spot efficiency, related to an effect of the bias circuit, and find a way to rule out this contribution during data post-processing and directly in the experiment. From the data analysis for waveguide-integrated SNSPD, we find signatures of the saturation of the two-spot efficiency and hot-spot interaction length of order of 100 nm.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1187  
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