Zinoni, C., Alloing, B., Li, L. H., Marsili, F., Fiore, A., Lunghi, L., et al. (2007). Single-photonics at telecom wavelengths using nanowire superconducting single photon detectors. In CLEO/QELS (QTuF6 (1 to 2)). Optical Society of America.
Abstract: Novel single-photon detectors based on NbN superconducting nanostructures promise orders-of- magnitude improvement over InGaAs APDs. We demonstrate this improved performance for the first time by measuring the g(2)(τ) on single photon states produced by a quantum dot at telecom wavelength.
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Kerman, A. J., Dauler, E. A., Yang, J. K. W., Rosfjord, K. M., Anant, V., Berggren, K. K., et al. (2007). Constriction-limited detection efficiency of superconducting nanowire single-photon detectors. Appl. Phys. Lett., 90(10), 101110 (1 to 3).
Abstract: We investigate the source of the large variations in the observed detection efficiencies of superconducting nanowire single-photon detectors between many nominally identical devices. Through both electrical and optical measurements, we infer that these variations arise from “constrictions:” highly localized regions of the nanowires where the effective cross-sectional area for superconducting current is reduced. These constrictions limit the bias-current density to well below its critical value over the remainder of the wire, and thus prevent the detection efficiency from reaching the high values that occur in these devices when they are biased near the critical current density.
This work is sponsored by the United States Air Force under Contract No. FA8721-05-C-0002.
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Słysz, W., Węgrzecki, M., Bar, J., Grabiec, P., Górska, M., Zwiller, V., et al. (2006). Fiber-coupled single-photon detectors based on NbN superconducting nanostructures for practical quantum cryptography and photon-correlation studies. Appl. Phys. Lett., 88(26), 261113 (1 to 3).
Abstract: We have fabricated and tested a two-channel single-photon detector system based on two fiber-coupled superconducting single-photon detectors (SSPDs). Our best device reached the system quantum efficiency of 0.3% in the 1540-nm telecommunication wavelength with a fiber-to-detector coupling factor of about 30%. The photoresponse consisted of 2.5-ns-wide voltage pulses with a rise time of 250ps and timing jitter below 40ps. The overall system response time, measured as a second-order, photon cross-correlation function, was below 400ps. Our SSPDs operate at 4.2K inside a liquid-helium Dewar, but their optical fiber inputs and electrical outputs are at room temperature. Our two-channel detector system should find applications in practical quantum cryptography and in antibunching-type quantum correlation measurements.
The authors would like to thank Dr. Marc Currie for his assistance in early time-resolved photoresponse measurements and Professor Atac Imamoglu for his support. This work was supported by the Polish Ministry of Science under Project No. 3 T11B 052 26 (Warsaw), RFBR 03-02-17697 and INTAS 03-51-4145 grants (Moscow), CRDF Grant No. RE2-2531-MO-03 (Moscow), RE2-2529-MO-03 (Moscow and Rochester), and US AFOSR FA9550-04-1-0123 (Rochester). Additional funding was provided by the grants from the MIT Lincoln Laboratory and BBN Technologies Corp.
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Rosfjord, K. M., Yang, J. K. W., Dauler, E. A., Anant, V., Berggren, K. K., Kerman, A. J., et al. (2006). Increased detection efficiencies of nanowire single-photon detectors by integration of an optical cavity and anti-reflection coating. In CLEO/QELS (JTuF2 (1 to 2)).
Abstract: We fabricate and test superconducting NbN-nanowire single-photon detectors with an integrated optical cavity and anti-reflection coating. We design the cavity and coating such as to maximize absorption in the NbN film of the detector.
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Chulkova, G., Milostnaya, I., Korneev, A., Minaeva, O., Rubtsova, I., Voronov, B., et al. (2005). Superconducting nanostructures for counting of single photons in the infrared range. In Proc. 2-nd CAOL (Vol. 2, pp. 100–103).
Abstract: We present our studies on ultrafast superconducting single-photon detectors (SSPDs) based on ultrathin NbN nanostructures. Our SSPDs are patterned by electron beam lithography from 4-nm thick NbN film into meander-shaped strips covering square area of 10/spl times/10 /spl mu/m/sup 2/. The advances in the fabrication technology allowed us to produce highly uniform 100-120-nm-wide strips with meander filling factor close to 0.6. The detectors exploit a combined detection mechanism, where upon a single-photon absorption, an avalanche of excited hot electrons and the biasing supercurrent, jointly produce a picosecond voltage transient response across the superconducting nanostrip. The SSPDs are typically operated at 4.2 K, but they have shown that their sensitivity in the infrared radiation range can be significantly improved by lowering the operating temperature from 4.2 K to 2 K. When operated at 2 K, the SSPD quantum efficiency (QE) for visible light photons reaches 30-40%, which is the saturation value limited by optical absorption of our 4-nm-thick NbN film. For 1.55 /spl mu/m photons, QE was /spl sim/20% and decreases exponentially with the increase of the optical wavelength, but even at the wavelength of 6 /spl mu/m the detector remains sensitive to single photons and exhibits QE of about 10/sup -2/%. The dark (false) count rate at 2 K is as low as 2 /spl times/ 10/sup -4/ s/sup -1/, what makes our detector essentially a background-limited sensor. The very low dark-count rate results in the noise equivalent power (NEP) as low as 10/sup -18/ WHz/sup -1/2/ for the mid-infrared range (6 /spl mu/m). Further improvement of the SSPD performance in the mid-infrared range can be obtained by substituting NbN for the other, lower-T/sub c/ superconductors with the narrow superconducting gap and low quasiparticle diffusivity. The use of such materials will shift the cutoff wavelength towards the values even longer than 6 /spl mu/m.
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Корнеева, Ю. П., Трифонов, А. В., Вахтомин, Ю. Б., Смирнов, К. В., Корнеев, А. А., Рябчун, С. А., et al. (2012). Расчет согласующего оптического резонатора для сверхпроводникового нанополоскового детектора. Преподаватель ХХI век, (3), 225–227.
Abstract: В статье произведен расчет резонатора, предназначенного для согласования сверхпроводникового нанополоскового однофотонного детектора с оптическим сигналом. Показано, что для детектора, выполненного из пленки с типичным сопротивлением квадрата 500 Ом и коэффициентом заполнения 0.5 коэффициент согласования с излучением, поляризованным параллельно полоскам детектора, достигает величины около 60%.
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Ozhegov, R., Elezov, M., Kurochkin, Y., Kurochkin, V., Divochiy, A., Kovalyuk, V., et al. (2014). Quantum key distribution over 300. In A. A. Orlikovsky (Ed.), Proc. SPIE (Vol. 9440, 1F (1 to 9)). SPIE.
Abstract: We discuss the possibility of polarization state reconstruction and measurement over 302 km by Superconducting Single- Photon Detectors (SSPDs). Because of the excellent characteristics and the possibility to be effectively coupled to singlemode optical fiber many applications of the SSPD have already been reported. The most impressive one is the quantum key distribution (QKD) over 250 km distance. This demonstration shows further possibilities for the improvement of the characteristics of quantum-cryptographic systems such as increasing the bit rate and the quantum channel length, and decreasing the quantum bit error rate (QBER). This improvement is possible because SSPDs have the best characteristics in comparison with other single-photon detectors. We have demonstrated the possibility of polarization state reconstruction and measurement over 302.5 km with superconducting single-photon detectors. The advantage of an autocompensating optical scheme, also known as “plugandplay” for quantum key distribution, is high stability in the presence of distortions along the line. To increase the distance of quantum key distribution with this optical scheme we implement the superconducting single photon detectors (SSPD). At the 5 MHz pulse repetition frequency and the average photon number equal to 0.4 we measured a 33 bit/s quantum key generation for a 101.7 km single mode ber quantum channel. The extremely low SSPD dark count rate allowed us to keep QBER at 1.6% level.
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Takemoto, K., Nambu, Y., Miyazawa, T., Sakuma, Y., Yamamoto, T., Yorozu, S., et al. (2015). Quantum key distribution over 120 km using ultrahigh purity single-photon source and superconducting single-photon detectors. Sci. Rep., 5, 14383.
Abstract: Advances in single-photon sources (SPSs) and single-photon detectors (SPDs) promise unique applications in the field of quantum information technology. In this paper, we report long-distance quantum key distribution (QKD) by using state-of-the-art devices: a quantum-dot SPS (QD SPS) emitting a photon in the telecom band of 1.5 μm and a superconducting nanowire SPD (SNSPD). At the distance of 100 km, we obtained the maximal secure key rate of 27.6 bps without using decoy states, which is at least threefold larger than the rate obtained in the previously reported 50-km-long QKD experiment. We also succeeded in transmitting secure keys at the rate of 0.307 bps over 120 km. This is the longest QKD distance yet reported by using known true SPSs. The ultralow multiphoton emissions of our SPS and ultralow dark count of the SNSPD contributed to this result. The experimental results demonstrate the potential applicability of QD SPSs to practical telecom QKD networks.
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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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Glejm, A. V., Anisimov, A. A., Asnis, L. N., Vakhtomin, Y. B., Divochiy, A. V., Egorov, V. I., et al. (2014). Quantum key distribution in an optical fiber at distances of up to 200 km and a bit rate of 180 bit/s. Bulletin of the Russian Academy of Sciences. Physics, 78(3), 171–175.
Abstract: An experimental demonstration of a subcarrier-wave quantum cryptography system with superconducting single-photon detectors (SSPDs) that distributes a secure key in a single-mode fiber at distance of 25 km with a bit rate of 800 kbit/s, a distance of 100 km with a bit rate of 19 kbit/s, and a distance of 200 km with a bit rate of 0.18 kbit/s is described.
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Morozov, P., Lukina, M., Shirmanova, M., Divochiy, A., Dudenkova, V., Gol'tsman, G. N., et al. (2021). Singlet oxygen phosphorescence imaging by superconducting single-photon detector and time-correlated single-photon counting. Opt. Lett., 46(6), 1217–1220.
Abstract: This Letter presents, to the best of our knowledge, a novel optical configuration for direct time-resolved measurements of luminescence from singlet oxygen, both in solutions and from cultured cells on photodynamic therapy. The system is based on the superconducting single-photon detector, coupled to the confocal scanner that is modified for the near-infrared measurements. The recording of a phosphorescence signal from singlet oxygen at 1270 nm has been done using time-correlated single-photon counting. The performance of the system is verified by measuring phosphorescence from singlet oxygen generated by the photosensitizers commonly used in photodynamic therapy: methylene blue and chlorin e6. The described system can be easily upgraded to the configuration when both phosphorescence from singlet oxygen and fluorescence from the cells can be detected in the imaging mode. Thus, co-localization of the signal from singlet oxygen with the areas inside the cells can be done.
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Rosfjord, K. M., Yang, J. K. W., Dauler, E. A., Kerman, A. J., Vikas Anant, Voronov, B. M., et al. (2006). Nanowire Single-photon detector with an integrated optical cavity and anti-reflection coating. Opt. Express, 14(2), 527–534.
Abstract: We have fabricated and tested superconducting single-photon detectors and demonstrated detection efficiencies of 57% at 1550-nm wavelength and 67% at 1064 nm. In addition to the peak detection efficiency, a median detection efficiency of 47.7% was measured over 132 devices at 1550 nm. These measurements were made at 1.8K, with each device biased to 97.5% of its critical current. The high detection efficiencies resulted from the addition of an optical cavity and anti-reflection coating to a nanowire photodetector, creating an integrated nanoelectrophotonic device with enhanced performance relative to the original device. Here, the testing apparatus and the fabrication process are presented. The detection efficiency of devices before and after the addition of optical elements is also reported.
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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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Пентин, И. В., Смирнов, К. В., Вахтомин, Ю. Б., Смирнов, А. В., Ожегов, Р. В., Дивочий, А. В., et al. (2011). Быстродействующий терагерцевый приемник и инфракрасный счетчик одиночных фотонов на эффекте разогрева электронов в сверхпроводниковых тонкопленочных наноструктурах. Труды МФТИ, 3(2), 38–42.
Abstract: Представлены результаты создания приемных систем терагерцевого диапазона (0.3-70 ТГц), обладающих рекордным быстродействием (50 пс) и высокой чувствительностью (до 5x 10^(-14) Вт/Гц^(1/2)), а также однофотонных приемных систем ближнего инфракрасного диапазона с квантовой эффективностью 25 %, уровнем темнового счета 10-1c., максимальной скоростью счета ~ 100 МГц и временным разрешением до 50 пс.
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Smirnov, K. V., Vakhtomin, Y. B., Divochiy, A. V., Ozhegov, R. V., Pentin, I. V., & Gol'tsman, G. N. (2010). Infrared and terahertz detectors on basis of superconducting nanostructures. In IEEE (Ed.), Microwave and Telecom. Technol. (CriMiCo), 20th Int. Crimean Conf. (pp. 823–824).
Abstract: Results of development of single-photon receiving systems of visible, infrared and terahertz range based on thin-film superconducting nanostructures are presented. The receiving systems are produced on the basis of superconducting nanostructures, which function by means of hot-electron phenomena.
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