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Huebers, H. - W., Pavlov, S., Semenov, A., Köhler, R., Mahler, L., Tredicucci, A., et al. (2005). Terahertz quantum cascade laser as local oscillator in a heterodyne receiver. Optics Express, 13(15), 5890–5896.
Abstract: Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same result as with a gas laser as local oscillator.
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Rabanus, D., Graf, U. U., Philipp, M., Ricken, O., Stutzki, J., Vowinkel, B., et al. (2009). Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver. Optics Express, 17(3), 1159–1168.
Abstract: We demonstrate for the first time the closure of an electronic phase lock loop for a continuous–wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency (IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark–shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K.
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Масленникова, А. В., Рябчун, С. А., Финкель, М. И., Каурова, Н. С., Исупова, А. А., Воронов, Б. М., et al. (2011). Широкополосные смесители на горячих электронах на основе NbN наноструктур. Труды МФТИ, 3(2), 31–34.
Abstract: Мы приводим данные исследования полосы преобразования смесителей на горячих электронах (hot-electron bolometer, НЕВ), изготовленных на основе тонких пленок NbN. Зависимость полосы преобразования от длины смесительного элемента находится в прекрасном согласии с результатами теоретической модели HEB-смесителя, в котором энергетическая релаксация электронов одновременно происходит по двум каналам: фононному и диффузионному.
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de Lange, G., Krieg, J. - M., Honingh, N., Karpov, A., & Cherednichenko, S. (2008). Performance of the HIFI flight mixers. In Proc. 19th Int. Symp. Space Terahertz Technol. (pp. 98–105).
Abstract: We summarize the technology and final results of the superconducting heterodyne SIS and HEB mixers that are developed for the HIFI instrument. Within HIFI 7 frequency bands cover the frequency range from 480 GHz to 1910 GHz. We describe the different device technologies and optical coupling schemes that are used to cover the frequency bands. The efforts of the different mixer teams that participate in HIFI have contributed to an instrument that will have unprecedented sensitivity and frequency coverage.
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Братман, В. Л., Литвак, А. Г., & Суворов, Е. В. (2010). Освоение терагерцевого диапазона: источники и приложения. Успехи физ. наук, 181(8), 867–874.
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