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Pentin, I., Finkel, M., Maslennikov, S., Vakhtomin, Y., Smirnov, K., Kaurova, N., et al. (2017). Superconducting hot-electron-bolometer mixers for the mid-IR. Rus. J. Radio Electron., (10), http://jre.cplire.ru/jre/oct17/9/text.pdf. Retrieved July 5, 2024, from http://jre.cplire.ru/jre/oct17/9/abstract_e.html
Abstract: The work presents the result of development of the NbN superconducting hot-electron-bolometer (HEB) mixer. The sensitive element of the mixer is directly coupled to mid-IR radiation, and doesn’t have planar metallic antenna. Investigations of noise characteristics of NbN HEB mixer were performed at the frequency 28.4 THz (λ = 10.6 µm) by using gas-discharge CW CO2-laser without consideration of optical and electrical losses in the heterodyne receiver. The noise temperature of NbN HEB mixer with the size of the sensitive element 10 µm × 10 µm was 2320 K (~ 1.5hν/kB) at the heterodyne frequency of 28.4 THz. The noise temperature was determined by measuring the Y-factor taking into account the term which describes fluctuations of zero-point oscillations in accordance with the fluctuation-dissipation theorem of Calle-Welton. Isothermal method was used to estimate the absorbed heterodyne radiation power which was 9 µW at the optimal operating point for the minimum noise temperature of NbN HEB mixer.
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Ryabchun, S., Tong, C. -yu E., Blundell, R., Kimberk, R., & Gol’tsman, G. (2006). Effect of microwave radiation on the stability of terahertz hot-electron bolometer mixers. In M. Anwar, A. J. DeMaria, & M. S. Shur (Eds.), Proc. SPIE (Vol. 6373, 63730J (1 to 5)). SPIE.
Abstract: We report our studies of the effect of microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the NbN hot-electron bolometer (HEB) mixer incorporated into a THz heterodyne receiver. It is shown that exposing the HEB mixer to microwave radiation does not result in a significant rise of the receiver noise temperature and degradation of the mixer conversion gain so long as the level of microwave power is small compared to the local oscillator drive. Hence the injection of a small, but controlled amount of microwave radiation enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the stability of HEB mixer receivers.
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Gao, J. R., Hajenius, M., Baselmans, J. J. A., Klapwijk, T. M., de Korte, P. A. J., Voronov, B., et al. (2004). NbN hot electron bolometer mixers with superior performance for space applications. In E. Armandillo, & B. Leone (Eds.), Proc. Int. workshop on low temp. electronics (pp. 11–17). Noordwijk.
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Yagoubov, P., Hübers, H. - W., Gol’tsman, G., Semenov, A., Gao, J., Hoogeveen, R., et al. (2001). Hot-electron bolometer mixers – technology for far-infrared heterodyne instruments in future atmospheric chemistry missions. In S. Buehler, & Berlin (Eds.), Proc. 3rd Int. Symp. Submillimeter Wave Earth Observation From Space (pp. 57–69). Logos-Verlag.
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Huebers, H. - W., Schubert, J., Semenov, A., Gol’tsman, G. N., Voronov, B. M., Gershenzon, E. M., et al. (1999). NbN phonon-cooled hot-electron bolometer as a mixer for THz heterodyne receivers. In J. M. Chamberlain (Ed.), Proc. SPIE (Vol. 3828, pp. 410–416). Spie.
Abstract: We have investigated a phonon-cooled NbN hot electron bolometric (HEB) mixer in the frequency range from 0.7 THz to 5.2 THz. The device was a 3.5 nm thin film with an in- plane dimension of 1.7 X 0.2 micrometers 2 integrated in a complementary logarithmic spiral antenna. The measured DSB receiver noise temperatures are 1500 K, 2200 K, 2600 K, 2900 K, 4000 K, 5600 K and 8800 K. The sensitivity fluctuation, the long term stability, and the antenna pattern were measured and the suitability of the mixer for a practical heterodyne receiver is discussed.
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Baubert, J., Salez, M., Delorme, Y., Pons, P., Goltsman, G., Merkel, H., et al. (2003). Membrane-based HEB mixer for THz applications. In J. - C. Chiao, V. K. Varadan, & C. Cané (Eds.), Proc. SPIE (Vol. 5116, pp. 551–562). SPIE.
Abstract: We report in this paper a new concept for 2.7 THz superconducting Niobium nitride (NbN) Hot-Electron Bolometer mixer (HEB). The membrane process was developped for space telecommnunication applications a few years ago and the HEB mixer concept is now considered as the best choice for low-noise submillimeter-wave frequency heterodyne receivers. The idea is then to join these two technologies. The novel fabrication scheme is to fabricate a NbN HEB mixer on a 1 μm thick stress-less Si3N4/SiO2 membrane. This seems to present numerous improvements concerning : use at higher RF frequencies, power coupling efficiency, HEB mixer sensitivity, noise temperature, and space applications. This work is to be continued within the framework of an ESA TRP project, a 2.7 THz heterodyne camera with numerous applications including a SOFIA airborne receiver. This paper presents the whole fabrication process, the validation tests and preliminary results. Membrane-based HEB mixer theory is currently being investigated and further tests such as heterodyne and Fourier transform spectrometry measurement are planed shortly.
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Vahtomin, Y. B., Finkel, M. I., Antipov, S. V., Voronov, B. M., Smirnov, K. V., Kaurova, N. S., et al. (2002). Gain bandwidth of phonon-cooled HEB mixer made of NbN thin film with MgO buffer layer on Si. In Harvard university (Ed.), Proc. 13th Int. Symp. Space Terahertz Technol. (pp. 259–270). Cambridge, MA, USA.
Abstract: We present recently obtained values for gain bandwidth of NbN HEB mixers for different substrates and film thicknesses and for MgO buffer layer on Si at LO frequency of 0.85-1 THz. The maximal bandwidth, 5.2 GHz, was achieved for the device on MgO buffer layer on Si with a 2 nm thick NbN film. Functional devices based on NbN films of such thickness were fabricated for the first time due to an improvement of superconducting properties of NbN film deposited on MgO buffer layer on Si substrate.
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Meledin, D., Tong, C. Y. - E., Blundell, R., Kaurova, N., Smirnov, K., Voronov, B., et al. (2002). The sensitivity and IF bandwidth of waveguide NbN hot electron bolometer mixers on MgO buffer layers over crystalline quartz. In Harvard university (Ed.), Proc. 13th Int. Symp. Space Terahertz Technol. (pp. 65–72). Cambridge, MA, USA.
Abstract: We have developed and characterized waveguide phonon-cooled NbN Hot Electron Bolometer (FMB) mixers fabricated from a 3-4 nm thick NbN film deposited on a 200nm thick MgO buffer layer over crystalline quartz. Double side band receiver noise temperatures of 900-1050 K at 1.035 THz, and 1300-1400 K at 1.26 THz have been measured at an intermediate frequency of 1.5 GHz. The intermediate frequency bandwidth, measured at 0.8 THz LO frequency, is 3.2 GHz at the optimal bias point for low noise receiver operation.
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Cherednichenko, S., Kroug, M., Khosropanah, P., Adam, A., Merkel, H., Kolberg, E., et al. (2002). A broadband terahertz heterodyne receiver with an NbN HEB mixer. In Harward University (Ed.), Proc. 13th Int. Symp. Space Terahertz Technol. (pp. 85–95). Cambridge, MA, USA.
Abstract: We present a broadband and low noise heterodyne receiver for 1.4-1.7 THz designed for the Hershel Space Observatory. A phonon- cooled NbN HEB mixer was integrated with a normal metal double- slot antenna and an elliptical silicon lens. DSB receiver noise temperature Tr was measured from 1 GHz through 8GHz intermediate frequency band with 50 MHz instantaneous bandwidth. At 4.2 K bath temperature and at 1.6 THz LO frequency Tr is 800 K with the receiver noise bandwidth of 5 GHz. While at 2 K bath temperature Tr was as low as 700 K. At 0.6 THz and 1.1 THz a spiral antenna integrated NbN HEB mixer showed the receiver noise temperature 500 K and 800 K, though no antireflection coating was used in this case. Tr of 1100 K was achieved at 2.5 THz while the receiver noise bandwidth was 4 GHz.
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Yngvesson, K. S., Gerecht, E., Musante, C. F., Zhuang, Y., Ji, M., Goyette, T. M., et al. (1999). Low-noise HEB heterodyne receivers and focal plane arrays for the THz regime using NbN. In R. J. Hwu, & K. Wu (Eds.), Proc. SPIE (Vol. 3795, pp. 357–368). SPIE.
Abstract: We have developed prototype HEB receivers using thin film superconducting NbN devices deposited on silicon substrates. The devices are quasi-optically coupled through a silicon lens and a self-complementary log-specific toothed antenna. We measured DSB receiver noise temperatures of 500 K (13 X hf/2k) at 1.56 THz and 1,100 K (20 X hf/2k) at 2.24 THz. Noise temperatures are expected to fall further as devices and quasi-optical coupling methods are being optimized. The measured 3 dB IF conversion gain bandwidth for one device was 3 GHz, and it is estimated that the bandwidth over which the receiver noise temperature is within 3 dB of its minimum value is 6.5 GHz which is sufficient for a number of practical applications. We will discuss our latest results and give a detailed description of our prototype setup and experiments. We will also discuss our plans for developing focal plane arrays with tens of Hot Electron Bolometric mixer elements on a single silicon substrate which will make real time imaging systems in the THz region feasible.
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