Zhang, X., Lita, A. E., Smirnov, K., Liu, H. L., Zhu, D., Verma, V. B., et al. (2020). Strong suppression of the resistivity near the superconducting transition in narrow microbridges in external magnetic fields. Phys. Rev. B, 101(6), 060508 (1 to 6).
Abstract: We have investigated a series of superconducting bridges based on homogeneous amorphous WSi and MoSi films, with bridge widths w ranging from 2 to 1000μm and film thicknesses d∼4−6 and 100 nm. Upon decreasing the bridge widths below the respective Pearl lengths, we observe in all cases distinct changes in the characteristics of the resistive transitions to superconductivity. For each of the films, the resistivity curves R(B,T) separate at a well-defined and field-dependent temperature T∗(B) with decreasing the temperature, resulting in a dramatic suppression of the resistivity and a sharpening of the transitions with decreasing bridge width w. The associated excess conductivity in all the bridges scales as 1/w, which may suggest either the presence of a highly conducting region that is dominating the electric transport, or a change in the vortex dynamics in narrow enough bridges. We argue that this effect can only be observed in materials with sufficiently weak vortex pinning.
|
Shcheslavskiy, V., Morozov, P., Divochiy, A., Vakhtomin, Y., Smirnov, K., & Becker, W. (2016). Erratum: “Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector” [Rev. Sci. Instrum. 87, 053117 (2016)] (Vol. 87).
Abstract: In the original paper1the Ref. 10 should be M. Sanzaro, N. Calandri, A. Ruggeri, C. Scarcella, G. Boso, M. Buttafava, and A. Tosi, Proc. SPIE9370, 93701T (2015).
|
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.
|
Korneev, A., Minaeva, O., Rubtsova, I., Milostnaya, I., Chulkova, G., Voronov, B., et al. (2005). Superconducting single-photon ultrathin NbN film detector. Quantum Electronics, 35(8), 698–700.
Abstract: Superconducting single-photon ultrathin NbN film detectors are studied. The development of manufacturing technology of detectors and the reduction of their operating temperature down to 2 K resulted in a considerable increase in their quantum efficiency, which reached in the visible region (at 0.56 μm) 30%—40%, i.e., achieved the limit determined by the absorption coefficient of the film. The quantum efficiency exponentially decreases with increasing wavelength, being equal to ~20% at 1.55 μm and ~0.02% at 5 μm. For the dark count rate of ~10-4s-1, the experimental equivalent noise power was 1.5×10-20 W Hz-1/2; it can be decreased in the future down to the record low value of 5×10-21 W Hz-1/2. The time resolution of the detector is 30 ps.
|
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.
|
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.
|
Korneeva, Y. P., Mikhailov, M. Y., Pershin, Y. P., Manova, N. N., Divochiy, A. V., Vakhtomin, Y. B., et al. (2014). Superconducting single-photon detector made of MoSi film. Supercond. Sci. Technol., 27(9), 095012.
Abstract: We fabricated and characterized nanowire superconducting single-photon detectors made of 4 nm thick amorphous Mox Si1−x films. At 1.7 K the best devices exhibit a detection efficiency (DE) up to 18% at 1.2 $\mu {\rm m}$ wavelength of unpolarized light, a characteristic response time of about 6 ns and timing jitter of 120 ps. The DE was studied in wavelength range from 650 nm to 2500 nm. At wavelengths below 1200 nm these detectors reach their maximum DE limited by photon absorption in the thin MoSi film.
|
Morozov, D. V., Smirnov, K. V., Smirnov, A. V., Lyakhov, V. A., & Goltsman, G. N. (2005). A millimeter-submillimeter phonon-cooled hot-electron bolometer mixer based on two-dimensional electron gas in an AlGaAs/GaAs heterostructure. Semicond., 39(9), 1082–1086.
Abstract: Experimental results obtained by studying the main characteristics of a millimeter-submillimeter wave mixer based on the hot-electron effect in a two-dimensional electron gas in a AlGaAs/GaAs heterostructure with a phonon-scattering cooling mechanism for charge carriers are reported. The gain bandwidth of the mixer is 4 GHz, the internal conversion losses are 13 dB, and the optimum local-oscillator power is 0.5 μW (for a mixer area of 1 μm2). It is shown that a millimeter-submillimeter-wave receiver with a noise temperature of 1900 K can be developed on the basis of a AlGaAs/GaAs mixer. This mixer also appears to be promising for use in array receiver elements.
|
Gol’tsman, G. N., & Smirnov, K. V. (2001). Electron-phonon interaction in a two-dimensional electron gas of semiconductor heterostructures at low temperatures. Jetp Lett., 74(9), 474–479.
Abstract: Theoretical and experimental works devoted to studying electron-phonon interaction in the two-dimensional electron gas of semiconductor heterostructures at low temperatures in the case of strong heating in an electric field under quasi-equilibrium conditions and in a quantizing magnetic field perpendicular to the 2D layer are considered.
|
Verevkin, A., Pearlman, A., Slysz, W., Zhang, J., Currie, M., Korneev, A., et al. (2004). Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications. J. Modern Opt., 51(9-10), 1447–1458.
Abstract: The paper reports progress on the design and development of niobium-nitride, superconducting single-photon detectors (SSPDs) for ultrafast counting of near-infrared photons for secure quantum communications. The SSPDs operate in the quantum detection mode, based on photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-width superconducting stripe. The devices are fabricated from 3.5 nm thick NbN films and kept at cryogenic (liquid helium) temperatures inside a cryostat. The detector experimental quantum efficiency in the photon-counting mode reaches above 20% in the visible radiation range and up to 10% at the 1.3–1.55 μn infrared range. The dark counts are below 0.01 per second. The measured real-time counting rate is above 2 GHz and is limited by readout electronics (the intrinsic response time is below 30 ps). The SSPD jitter is below 18 ps, and the best-measured value of the noise-equivalent power (NEP) is 2 × 10−18 W/Hz1/2. at 1.3 μm. In terms of photon-counting efficiency and speed, these NbN SSPDs significantly outperform semiconductor avalanche photodiodes and photomultipliers.
|
