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| Author | Lobanov, Y.; Tong, E.; Blundell, R.; Hedden, A.; Voronov, B.; Gol'tsman, G. | ||||
| Title | Large-signal frequency response of an HEB mixer: from 300 MHz to terahertz | Type | Journal Article | ||
| Year | 2011 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | |
| Volume | 21 | Issue | 3 | Pages | 628-631 |
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | We present a study of the large signal frequency response of an HEB mixer over a wide frequency range. In our experiments, we have subjected the HEB mixer to incident electromagnetic radiation from 0.3 GHz to 1 THz. The mixer element is an NbN film deposited on crystalline quartz. The mixer chip is mounted in a waveguide cavity, coupled to free space with a diagonal horn. At microwave frequencies, electromagnetic radiation is applied through the coaxial bias port of the mixer block. At higher frequencies the input signal passes via the diagonal horn feed. At each frequency, the incident power is varied and a family of I-V curves is recorded. From the curves we identify 3 distinct regimes of operation of the mixer separated by the phonon relaxation frequency and the superconducting energy gap frequency observed at about 3 GHz and 660 GHz respectively. In this paper, we will present observed curves and discuss the results of our experiment. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 719 | ||
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| Author | Lobanov, Y.V.; Tong, C.-Y.E.; Hedden, A.S.; Blundell, R.; Voronov, B.M.; Gol'tsman, G.N. | ||||
| Title | Direct measurement of the gain and noise bandwidths of HEB mixers | Type | Journal Article | ||
| Year | 2011 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 21 | Issue | 3 | Pages | 645-648 |
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | The intermediate frequency (IF) bandwidth of a hot electron bolometer (HEB) mixer is an important parameter of the mixer, in that it helps to determine its suitability for a given application. With the availability of wideband low noise amplifiers, it is simple to measure the performance of an HEB mixer over a wide range of IF at a fixed LO frequency using the standard Y-factor method. This in-situ method allows us to measure both the gain and noise bandwidths simultaneously. We have also measured mixer output impedance with a vector network analyser. Intrinsic time constant has been extracted from the impedance data and compared to the mixer's bandwidths determined from receiver Y-factor measurement. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 720 | ||
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| Author | Васильева, И. А.; Компанеец, В. В.; Красная, Ж. А.; Чижикова, З. А. | ||||
| Title | Проявление внутримолекулярных вибронных взаимодействий в тонкоструктурных спектрах флуоресценции и возбуждения флуоресценции полиеновых δ-диметиламинокетонов | Type | Journal Article | ||
| Year | 2011 | Publication | Оптический журнал | Abbreviated Journal | Опт. ж. |
| Volume | 78 | Issue | 5 | Pages | 3-8 |
| Keywords | спектры флуоресценции; вибрационный анализ; адиабатическое гармоническое приближение; бесфононная линия; фононное крыло | ||||
| Abstract | Проведен вибрационный анализ спектров флуоресценции и возбуждения флуоресценции, полученных методом Шпольского при 4,2 K. Рассчитаны параметры внутримолекулярных взаимодействий двух δ-диметиламинокетонов. Для определения интегральных интенсивностей вибронных полос в спектрах с тонкой структурой на интенсивном сплошном фоне выполнено моделирование спектров путем представления полосы каждого из вибронных переходов бесфононной линией и фононным крылом с определенными параметрами (полуширинами, фактором Дебая–Валлера). Показано, что нарушение зеркальной симметрии в сопряженных спектрах флуоресценции и возбуждения флуоресценции этих двух соединений может быть обÑŠяснено интерференцией франк-кондоновского и герцберг-теллеровского взаимодействий. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 721 | ||
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| Author | Seleznev, V. A.; Tarkhov, M. A.; Voronov, B. M.; Milostnaya, I. I.; Lyakhno, V. Yu; Garbuz, A. S.; Mikhailov, M. Yu; Zhigalina, O. M.; Gol'tsman, G. N. | ||||
| Title | Deposition and characterization of few-nanometers-thick superconducting Mo-Re films | Type | Journal Article | ||
| Year | 2008 | Publication | Supercond. Sci. Technol. | Abbreviated Journal | Supercond. Sci. Technol. |
| Volume | 21 | Issue | 11 | Pages | 115006 (1 to 6) |
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| Abstract | We report on the fabrication and investigation of few-nanometers-thick superconducting molybdenum-rhenium (Mo-Re) films intended for use in nanowire single-photon superconducting detectors (SSPDs). Mo-Re films were deposited on sapphire substrates by DC magnetron sputtering of an Mo(60)-Re(40) alloy target in an atmosphere of argon. The films 2-10 nm thick had critical temperatures (Tc) from 5.6 to 9.7 K. HRTEM (high-resolution transmission electron microscopy) analysis showed that the films had a homogeneous structure. XPS (x-ray photoelectron spectroscopy) analysis showed the Mo to Re atom ratio to be 0.575/0.425, oxygen concentration to be 10%, and concentration of other elements to be 1%. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 723 | ||
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| Author | Lobanov, Y.; Tong, C.; Blundell, R.; Gol'tsman, G. | ||||
| Title | A study of direct detection effect on the linearity of hot electron bolometer mixers | Type | Conference Article | ||
| Year | 2009 | Publication | Proc. 20th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 20th ISSTT |
| Volume | Issue | Pages | 282-287 | ||
| Keywords | HEB mixer, direct detection effect | ||||
| Abstract | We have performed a study of how direct detection affects the linearity and hence the calibration of an HEB mixer. Two types of waveguide HEB devices have been used: a 0.8 THz HEB mixer and a 1.0 THz HEB mixer which is ~5 times smaller than the former. Two independent experimental approaches were used. In the ΔG/G method, the conversion gain of the HEB mixer is first measured as a function of the bias current for a number of bias voltages. At each bias setting, we carefully measure the change in the operating current when the input loads are switched. From the measured data, we can derive the expected difference in gain between the hot and cold loads. In the second method (injection method [1]), the linearity of the HEB mixer is independently measured by injecting a modulated signal for different input load temperatures. The results of both approaches confirm that there is gain compression in the operation of HEB mixers. Based on the results of our measurements, we discuss the impact of direct detection effects on the operation of HEB mixers. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 724 | ||
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| Author | Lobanov, Y. V.; Tong, Cheuk-Yu E.; Hedden, A. S.; Blundell, R.; Gol'tsman, G. N. | ||||
| Title | Microwave-assisted슠measurement슠of the슠frequency슠response슠of슠terahertz슠HEB슠mixers슠with a슠fourier슠transform슠spectrometer | Type | Conference Article | ||
| Year | 2010 | Publication | 21st International Symposium on Space Terahertz Technology | Abbreviated Journal | 21st ISSTT |
| Volume | Issue | Pages | 420-423 | ||
| Keywords | HEB mixer | ||||
| Abstract | We describe a novel method of operation of the HEB direct detector for use with a Fourier Transform Spectrometer. Instead of elevating the bath temperature, we have measured the RF response of waveguide HEB mixers by applying microwave radiation to select appropriate bias conditions. In our experiment, a microwave signal is injected into the HEB mixer via its IF port. By choosing an appropriate injection level, the device can be operated close to the desired operating point. Furthermore, we have shown that both thermal biasing and microwave injection can reproduce the same spectral response of the HEB mixer. However, with the use of microwave injection, there is no need to wait for the mixer to reach thermal equilibrium, so characterisation can be done in less time. Also, the liquid helium consumption for our wet cryostat is also reduced. We have demonstrated that the signalto-noise ratio of the FTS measurements can be improved with microwave injection. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 725 | ||
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| Author | Ожегов, Р.В.; Окунев, О.В.; Гольцман, Г.Н. | ||||
| Title | Флуктуационная чувствительность сверхпроводящего болометрического смесителя на эффекте разогрева электронного газа | Type | Journal Article | ||
| Year | 2009 | Publication | Радиотехника | Abbreviated Journal | |
| Volume | Issue | 3 | Pages | 120-124 | |
| Keywords | смеситель на горячих электронах; флуктуационная чувствительность; тепловизор терагерцевого диапазона частот; hot-electron bolometer mixer; Imaging system; Noise equivalent temperature difference; Heterodyne receiver; Terahertz range | ||||
| Abstract | Interest in research in the terahertz range is driven by a great number of various applications, where terahertz instruments may play a leading role. To name just a few, such applications include study of the cosmic microwave background radiation and the distribution of the dark matter, medicine, navigation, fire alarm, security systems and environmental monitoring. The paper discusses the possibility of using a receiver based on the hot-electron effect in superconducting films as an imaging system. We present the results of the noise equivalent temperature difference (NETD) measurements performed with a hot-electron bolometer mixer made from a thin superconducting film. The receiver with a noise temperature of ~ 3800 K at a local oscillator frequency of 300 GHz a bandwidth of 500 MHz and an integration time of 1 s has offered an NETD of 0.5 K. We have also developed a technique that enabled us to reduce the contribution of the mixer gain fluctuations to the overall system instability. As of this writing, the above value of the NETD is the lowest value offered for this type of receiver, which indicates the possibility to use such receivers in real-time imaging systems. The technique offered in the paper for achieving the limiting value of the NETD offers an alternative to the phase-locking scheme. Представены результаты измерения флуктуационной чувствительности (NETD – noise equivalent temperature difference) болометрического смесителя на эффекте разогрева электронного газа в тонких сверхпроводящих пленках. Получено предельное значение NETD, равное 0,5 К, при шумовой температуре приемника 3800 К, ширине полосы преобразования 500 МГц, постоянной времени 1 с и частоте гетеродина 300 ГГц. Разработана методика достижения предельной флуктуационной чувствительности, позволяющая избежать влияния нестабильности коэффициента преобразования смесителя. |
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| Call Number | RPLAB @ gujma @ | Serial | 728 | ||
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| Author | Ожегов, Роман Викторович | ||||
| Title | Флуктуационная чувствительность и стабильность приемников с СИС и HEB смесителями для терагерцового тепловидения | Type | Journal Article | ||
| Year | 2011 | Publication | Радиофизика | Abbreviated Journal | |
| Volume | Issue | Pages | 135 | ||
| Keywords | HEB | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 731 | ||
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| Author | Чулкова, Г. М.; Семенов, А. В.; Корнеев, А. А.; Кардакова, А. И.; Аверьев, Н. В.; Ан, П. П.; Казаков, А. Ю.; Трифонов, А. В. | ||||
| Title | Спектральная чувствительность сверхпроводникового однофотонного детектора | Type | Journal Article | ||
| Year | 2011 | Publication | Журнал радиоэлектроники | Abbreviated Journal | Ж. радиоэлектрон. |
| Volume | 11 | Issue | Pages | 5 | |
| Keywords | SSPD; quantum efficiency; spectral sensitivity | ||||
| Abstract | We consider quantum efficiency dependence on photons' energy from hot spot model. Direction of quasiparticles diffusion drive across superconductive film. The maximal quantum efficiency is proportional to a probability of photon absorption. The spectral sensitivity of superconductive single photon detector does not have clearly expressed red limit. Changing regimes of work depends on a wavelength we can get high values of quantum efficiency in visible and infrared range which will be specified by the quality of fabrication of detectors and their consistency with the radiation. Key words: superconducting single-photon detector, SSPD, quantum efficiency, spectral sensitivity. В статье представлена зависимость квантовой эффективности от энергии фотона в рамках модели горячего пятна. Диффузия квазичастиц происходит в основном перпендикулярно направлению тока в областях с максимальной плотностью тока. Максимальная квантовая эффективность детектора пропорциональна вероятности поглощения фотона. Несмотря на квантовый характер работы сверхпроводникового однофотонного детектора, он не имеет четко выраженной красной границы. Изменяя режим работы в зависимости от длины волны можно в видимом и инфракрасном диапазонах получать высокие значения квантовой эффективности, которые будут определяться лишь качеством изготовления детекторов и степенью их согласования с излучением. |
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| Call Number | RPLAB @ gujma @ | Serial | 844 | ||
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| Author | Pernice, W.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G. N.; Sergienko, A. V.; Tang, H. X. | ||||
| Title | High speed and high efficiency travelling wave single-photon detectors embedded in nanophotonic circuits | Type | Miscellaneous | ||
| Year | 2012 | Publication | arXiv | Abbreviated Journal | arXiv |
| Volume | 1108.5299 | Issue | Pages | 1-23 | |
| Keywords | optical waveguides, waveguide SSPD, guantum photonics, jitter, detection efficiency | ||||
| Abstract | Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics. | ||||
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| Call Number | Serial | 845 | |||
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