Fedorov, G. E., Gaiduchenko, I. A., Golikov, A. D., Rybin, M. G., Obraztsova, E. D., Voronov, B. M., et al. (2015). Response of graphene based gated nanodevices exposed to THz radiation. In EPJ Web of Conferences (Vol. 103, 10003 (1 to 2)).
Abstract: In this work we report on the response of asymmetric graphene based devices to subterahertz and terahertz radiation. Our devices are made in a configuration of a field-effect transistor with conduction channel between the source and drain electrodes formed with a CVD-grown graphene. The radiation is coupled through a spiral antenna to source and top gate electrodes. Room temperature responsivity of our devices is close to the values that are attractive for commercial applications. Further optimization of the device configuration may result in appearance of novel terahertz radiation detectors.
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Sidorova, M., Semenov, A., Korneev, A., Chulkova, G., Korneeva, Y., Mikhailov, M., et al. (2018). Electron-phonon relaxation time in ultrathin tungsten silicon film. arXiv:1607.07321v1 [physics.ins-det].
Abstract: Using amplitude-modulated absorption of sub-THz radiation (AMAR) method, we studied electron-phonon relaxation in thin disordered films of tungsten silicide. We found a response time ~ 800 ps at critical temperature Tc = 3.4 K, which scales as minus 3 in the temperature range from 1.8 to 3.4 K. We discuss mechanisms, which can result in a strong phonon bottle-neck effect in a few nanometers thick film and yield a substantial difference between the measured time, characterizing response at modulation frequency, and the inelastic electron-phonon relaxation time. We estimate the electron-phonon relaxation time to be in the range ~ 100-200 ps at 3.4 K.
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Sidorova, M. V., Kozorezov, A. G., Semenov, A. V., Korneev, A. A., Chulkova, G. M., Korneeva, Y. P., et al. (2018). Non-bolometric bottleneck in electron-phonon relaxation in ultra-thin WSi film. arXiv:1607.07321v4 [physics.ins-det].
Abstract: We developed the model of the internal phonon bottleneck to describe the energy exchange between the acoustically soft ultrathin metal film and acoustically rigid substrate. Discriminating phonons in the film into two groups, escaping and nonescaping, we show that electrons and nonescaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultrathin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in tau{e-ph} = 140-190 ps at TC = 3.4 K, supporting the results of earlier measurements by independent techniques.
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Elezov, M. S., Ozhegov, R. V., Kurochkin, Y. V., Goltsman, G. N., Makarov, V. S., Samartsev, V. V., et al. (2015). Countermeasures against blinding attack on superconducting nanowire detectors for QKD. In EPJ Web Conf. (Vol. 103, 10002 (1 to 2)).
Abstract: Nowadays, the superconducting single-photon detectors (SSPDs) are used in Quantum Key Distribution (QKD) instead of single-photon avalanche photodiodes. Recently bright-light control of the SSPD has been demonstrated. This attack employed a “backdoor” in the detector biasing technique. We developed the autoreset system which returns the SSPD to superconducting state when it is latched. We investigate latched state of the SSPD and define limit conditions for effective blinding attack. Peculiarity of the blinding attack is a long nonsingle photon response of the SSPD. It is much longer than usual single photon response. Besides, we need follow up response duration of the SSPD. These countermeasures allow us to prevent blind attack on SSPDs for Quantum Key Distribution.
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Fedorov, G., Kardakova, A., Gayduchenko, I., Voronov, B. M., Finkel, M., Klapwijk, T. M., et al. (2014). Photothermoelectric response in asymmetric carbon nanotube devices exposed to sub-THz radiation. In Proc. 25th Int. Symp. Space Terahertz Technol. (71).
Abstract: This work reports on the voltage response of asymmetric carbon nanotube devices to sub-THz radiation at the frequency of 140 GHz. The devices contain CNT’s, which are over their length partially suspended and partially Van der Waals bonded to a SiO 2 substrate, causing a difference in thermal contact. Different heat sinking of CNTs by source and drain gives rise to temperature gradient and consequent thermoelectric power (TEP) as such a device is exposed to the sub-THz radiation. Sign of the DC signal, its power and gate voltage dependence observed at room temperature are consistent with this scenario. At liquid helium temperature the observed response is more complex. DC voltage signal of an opposite sign is observed in a narrow range of gate voltages at low temperatures and under low radiation power. We argue that this may indicate a true photovoltaic response from small gap (less than 10meV) CNT’s, an effect never reported before. While it is not clear if the observed effects can be used to develop efficient THz detectors we note that the responsivity of our devices exceeds that of CNT based devices in microwave or THz range reported before at room temperature. Besides at 4.2 K notable increase of the sample conductance (at least four-fold) is observed. Our recent results with asymmetric carbon nanotube devices response to THz radiation (2.5 THz) will also be presented.
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Pernice, W. H. P., Schuck, C., Minaeva, O., Li, M., Goltsman, G. N., Sergienko, A. V., et al. (2012). High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits. Nat. Commun., 3, 1325 (1 to 10).
Abstract: Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18 ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics.
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Ryabchun, S., Smirnov, A., Pentin, I., Vakhtomin, Y., Smirnov, K., Kaurova, N., et al. (2011). Superconducting single photon detector integrated with optical cavity. In Proc. MLPLIT (pp. 143–145). Modern laser physics and laser-information technologies for science and manufacture.
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Maslennikova, A., Larionov, P., Ryabchun, S., Smirnov, A., Pentin, I., Vakhtomin, Y., et al. (2011). Noise equivalent power and dynamic range of NBN hot-electron bolometers. In Proc. MLPLIT (pp. 146–148). Modern laser physics and laser-information technologies for science and manufacture.
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Korneev, A., Korneeva, Y., Florya, I., Voronov, B., & Goltsman, G. (2011). Spectral sensitivity of narrow strip NbN superconducting single-photon detector. In J. Fiurásek, & I. Prochazka (Eds.), Proc. SPIE (Vol. 8072, 80720G (1 to 9)). SPIE.
Abstract: Superconducting single-photon detector (SSPD) is patterned from 4-nm-thick NbN film deposited on sapphire substrate as a 100-nm-wide strip. Due to its high detection efficiency, low dark counts, and picosecond timing jitter SSPD has become a competitor to the InGaAs avalanche photodiodes at 1550 nm and longer wavelengths. Although the SSPD is operated at liquid helium temperature its efficient single-mode fibre coupling enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. In our strive to increase the detection efficiency at 1550 nm and longer wavelengths we developed and fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm. To increase the voltage response of the device we utilized cascade switching mechanism: we connected 50-nm-wide and 10-μm-long strips in parallel covering the area of 10 μmx10 μm. Absorption of a photon breaks the superconductivity in a strip leading to the bias current redistribution between other strips followed their cascade switching. As the total current of all the strips about is 1 mA by the order of magnitude the response voltage of such an SSPD is several times higher compared to the traditional meander-shaped SSPDs. In middle infrared (about 3 μm wavelength) these devices have the detection efficiency several times higher compared to the traditional SSPDs.
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Goltsman, G. (2009). Superconducting NbN hot-electron bolometer mixer, direct detector and single-photon counter: from devices to systems.
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