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Lobanov, Y. V., Vakhtomin, Y. B., Pentin, I. V., Rosental, V. A., Smirnov, K. V., Goltsman, G. N., et al. (2021). Time-resolved measurements of light–current characteristic and mode competition in pulsed THz quantum cascade laser. Optical Engineering, 60(8), 1–8.
Abstract: Quantum cascade lasers (QCL) are widely adopted as prominent and easy-to-use solid-state sources of terahertz radiation. Yet some applications require generation and detection of very sharp and narrow terahertz-range pulses with a specific spectral composition. We have studied time-resolved light-current (L–I) characteristics of multimode THz QCL operated with a fast ramp of the injection current. Detection of THz pulses was carried out using an NbN superconducting hot-electron bolometer with the time constant of the order of 1 ns while the laser bias current was swept during a single driving pulse. A nonmonotonic behavior of the L–I characteristic with several visually separated subpeaks was found. This behavior is associated with the mode competition in THz QCL cavity, which we confirm by L–I measurements with use of an external Fabry–Perot interferometer for a discrete mode selection. We also have demonstrated the possibility to control the L–I shape with suppression of one of the subpeaks by simply adjusting the off-axis parabolic mirror for optimal optical alignment for one of the laser modes. The developed technique paves the way for rapid characterization of pulsed THz QCLs for further studies of the possibilities of using this approach in remote sensing.
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Rasulova, G. K., Pentin, I. V., Vakhtomin, Y. B., Smirnov, K. V., Khabibullin, R. A., Klimov, E. A., et al. (2020). Pulsed terahertz radiation from a double-barrier resonant tunneling diode biased into self-oscillation regime. J. Appl. Phys., 128(22), 224303 (1 to 11).
Abstract: The study of the bolometer response to terahertz (THz) radiation from a double-barrier resonant tunneling diode (RTD) biased into the negative differential conductivity region of the I–V characteristic revealed that the RTD emits two pulses in a period of intrinsic self-oscillations of current. The bolometer pulse repetition rate is a multiple of the fundamental frequency of the intrinsic self-oscillations of current. The bolometer pulses are detected at two critical points with a distance between them being half or one-third of a period of the current self-oscillations. An analysis of the current self-oscillations and the bolometer response has shown that the THz photon emission is excited when the tunneling electrons are trapped in (the first pulse) and then released from (the second pulse) miniband states.
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Ren, Y., Zhang, D. X., Zhou, K. M., Miao, W., Zhang, W., Shi, S. C., et al. (2019). 10.6 μm heterodyne receiver based on a superconducting hot-electron bolometer mixer and a quantum cascade laser. AIP Advances, 9(7), 075307.
Abstract: We report on the development of a heterodyne receiver at mid-infrared wavelength for high-resolution spectroscopy applications. The receiver employs a superconducting NbN hot electron bolometer as a mixer and a room temperature distributed feedback quantum cascade laser operating at 10.6 μm (28.2 THz) as a local oscillator. The stabilization of the heterodyne receiver has been achieved using a feedback loop controlling the output power of the laser. Improved Allan variance times as well as a double sideband receiver noise temperature of 5000 K and a noise bandwidth of 2.8 GHz of the receiver system are demonstrated.
The work is supported in part by the National Key R&D Program of China under Grant 2018YFA0404701, by the CAS program under Grant QYZDJ-SSW-SLH043 and GJJSTD20180003, by the National Natural Science Foundation of China (NSFC) under Grant 11773083, by the “Hundred Talents Program” of the “Pioneer Initiative”, and in part by the CAS Key Lab for Radio Astronomy.
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Zinoni, C., Alloing, B., Li, L. H., Marsili, F., Fiore, A., Lunghi, L., et al. (2010). Erratum: “Single photon experiments at telecom wavelengths using nanowire superconducting detectors” [Appl. Phys. Lett. 91, 031106 (2007)]. Appl. Phys. Lett., 96(8), 089901.
Abstract: A calculation error was made in the original publication of this letter. The error was in the calculation of the noise equivalent power (NEP) values for the avalanche photodiode detector (APD) and the superconducting single photon detector (SSPD), the incorrect values were plotted on the right axis in Fig. 1(b). The correct NEP values were calculated with the same equation reported in the original letter and the revised Fig. 1(b) is shown below. The other conclusions of the paper remain unaltered.
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Zinoni, C., Alloing, B., Li, L. H., Marsili, F., Fiore, A., Lunghi, L., et al. (2007). Single-photon experiments at telecommunication wavelengths using nanowire superconducting detectors. Appl. Phys. Lett., 91(3), 031106 (1 to 3).
Abstract: The authors report fiber-coupled superconducting single-photon detectors with specifications that exceed those of avalanche photodiodes, operating at telecommunication wavelength, in sensitivity, temporal resolution, and repetition frequency. The improved performance is demonstrated by measuring the intensity correlation function g(2)(τ) of single-photon states at 1300nm produced by single semiconductor quantum dots.
This work was supported by Swiss National Foundation through the “Professeur borsier” and NCCR Quantum Photonics program, FP6 STREP “SINPHONIA” (Contract No. NMP4-CT-2005-16433), IP “QAP” (Contract No. 15848), NOE “ePIXnet,” and the Italian MIUR-FIRB program.
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Jiang, L., Antipov, S. V., Voronov, B. M., Gol'tsman, G. N., Zhang, W., Li, N., et al. (2007). Characterization of the performance of a quasi-optical NbN superconducting HEB mixer. IEEE Trans. Appl. Supercond., 17(2), 395–398.
Abstract: In this paper we focus mainly on the investigation of the performance of a quasi-optical (planar log-spiral antenna) phonon-cooled NbN superconducting hot electron bolometer (HEB) mixer, which is cryogenically cooled by a close-cycled 4-K cryocooler, at 500 and 850 GHz frequency bands. The mixer's noise performance, stability of IF output power, and local oscillator (LO) power requirement are characterized for three NbN superconducting HEB devices of different sizes. The transmission characteristics of Mylar and Zitex films with incidence waves of an elliptical polarization are also examined by measuring the mixer's noise temperature. The lowest receiver noise temperatures (with no corrections) of 750 and 1100 K are measured at 500 and 850 GHz, respectively. Experimental results also demonstrate that the bigger the HEB device is, the higher the stability of IF output power becomes.
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Jiang, L., Miao, W., Zhang, W., Li, N., Lin, Z. H., Yao, Q. J., et al. (2006). Characterization of a quasi-optical NbN superconducting HEB mixer. IEEE Trans. Microwave Theory Techn., 54(7), 2944–2948.
Abstract: In this paper, the performance of a quasi-optical NbN superconducting hot-electron bolometer (HEB) mixer, cryogenically cooled by a close-cycled 4-K refrigerator, is thoroughly investigated at 300, 500, and 850 GHz. The lowest receiver noise temperatures measured at the respective three frequencies are 1400, 900, and 1350 K, which can go down to 659, 413, and 529 K, respectively, after correcting the loss and associated noise contribution of the quasi-optical system before the measured superconducting HEB mixer. The stability of the quasi-optical superconducting HEB mixer is also investigated here. The Allan variance time measured with a local oscillator pumping at 500 GHz and an IF bandwidth of 110 MHz is 1.5 s at the dc-bias voltage exhibiting the lowest noise temperature and increases to 2.5 s at a dc bias twice that voltage.
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Vakhtomin, Y. B., Finkel, M. I., Antipov, S. V., Smirnov, K. V., Kaurova, N. S., Drakinskii, V. N., et al. (2003). The gain bandwidth of mixers based on the electron heating effect in an ultrathin NbN film on a Si substrate with a buffer MgO layer. J. of communications technol. & electronics, 48(6), 671–675.
Abstract: Measurements of the intermediate frequency band 900 GHz of mixers based on the electron heating effect (EHE) in 2-nm- and 3.5-nm-thick superconducting NbN films sputtered on MgO and Si substrates with buffer MgO layers are presented. A 2-nm-thick superconducting NbN film with a critical temperature of 9.2 K has been obtained for the first time using a buffer MgO layer.
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Antipov, S. V., Svechnikov, S. I., Smirnov, K. V., Vakhtomin, Y. B., Finkel, M. I., Goltsman, G. N., et al. (2001). Noise temperature of quasioptical NbN hot electron bolometer mixers at 900 GHz. Physics of Vibrations, 9(4), 242–245.
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Svechnikov, S. I., Antipov, S. V., Vakhtomin, Y. B., Goltsman, G. N., Gershenzon, E. M., Cherednichenko, S. I., et al. (2001). Conversion and noise bandwidths of terahertz NbN hot-electron bolometer mixers. Physics of Vibrations, 9(3), 205–210.
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