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Angeluts AA, Bezotosnyi VV, Cheshev EA, Goltsman GN, Finkel MI, Seliverstov SV, et al. Compact 1.64 THz source based on a dual-wavelength diode end-pumped Nd:YLF laser with a nearly semiconfocal cavity. Laser Phys. Lett.. 2014;11(1):015004 (1 to 4).
Abstract: We describe a compact dual-wavelength (1.047 and 1.053 μm) diode end-pumped Q-switched Nd:YLE laser source which has a number of applications in demand. In order to achieve its dual-wavelength operation it is suggested for the first time to use essentially nonmonotonous dependences of the threshold pump powers at these wavelengths on the cavity length in the region of the cavity semiconfocal configuration under a radius of the pump beam smaller than the radius of the zero Gaussian mode. Here we demonstrate one of the most interesting applications for this laser: difference frequency generation in a GaSe crystal at a frequency of 1.64 THz. A superconducting hot-electron bolometer is used to detect the THz power generated and to measure its pulse characteristics.
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Vetter A, Ferrari S, Rath P, Alaee R, Kahl O, Kovalyuk V, et al. Cavity-enhanced and ultrafast superconducting single-photon detectors. Nano Lett. 2016;16(11):7085–92.
Abstract: Ultrafast single-photon detectors with high efficiency are of utmost importance for many applications in the context of integrated quantum photonic circuits. Detectors based on superconductor nanowires attached to optical waveguides are particularly appealing for this purpose. However, their speed is limited because the required high absorption efficiency necessitates long nanowires deposited on top of the waveguide. This enhances the kinetic inductance and makes the detectors slow. Here, we solve this problem by aligning the nanowire, contrary to usual choice, perpendicular to the waveguide to realize devices with a length below 1 mum. By integrating the nanowire into a photonic crystal cavity, we recover high absorption efficiency, thus enhancing the detection efficiency by more than an order of magnitude. Our cavity enhanced superconducting nanowire detectors are fully embedded in silicon nanophotonic circuits and efficiently detect single photons at telecom wavelengths. The detectors possess subnanosecond decay ( approximately 120 ps) and recovery times ( approximately 510 ps) and thus show potential for GHz count rates at low timing jitter ( approximately 32 ps). The small absorption volume allows efficient threshold multiphoton detection.
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Pyatkov F, Khasminskaya S, Kovalyuk V, Hennrich F, Kappes MM, Goltsman GN, et al. Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers. Beilstein J Nanotechnol. 2017;8:38–44.
Abstract: Carbon nanotubes (CNTs) have recently been integrated into optical waveguides and operated as electrically-driven light emitters under constant electrical bias. Such devices are of interest for the conversion of fast electrical signals into optical ones within a nanophotonic circuit. Here, we demonstrate that waveguide-integrated single-walled CNTs are promising high-speed transducers for light-pulse generation in the gigahertz range. Using a scalable fabrication approach we realize hybrid CNT-based nanophotonic devices, which generate optical pulse trains in the range from 200 kHz to 2 GHz with decay times below 80 ps. Our results illustrate the potential of CNTs for hybrid optoelectronic systems and nanoscale on-chip light sources.
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Lobanov YV, Shcherbatenko ML, Semenov AV, Kovalyuk VV, Korneev AA, Goltsman GN, et al. Heterodyne spectroscopy with superconducting single-photon detector. In: EPJ Web Conf. Vol 132.; 2017. 01005.
Abstract: We demonstrate successful operation of a Superconducting Single Photon Detector (SSPD) as the core element in a heterodyne receiver. Irradiating the SSPD by both a local oscillator power and signal power simultaneously, we observed beat signal at the intermediate frequency of a few MHz. Gain bandwidth was found to coincide with the detector single pulse width, where the latter depends on the detector kinetic inductance, determined by the superconducting nanowire length.
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Titova N, Kardakova AI, Tovpeko N, Ryabchun S, Mandal S, Morozov D, et al. Slow electron–phonon cooling in superconducting diamond films. IEEE Trans Appl Supercond. 2017;27(4):1–4.
Abstract: We have measured the electron-phonon energy-relaxation time, τ eph , in superconducting boron-doped diamond films grown on silicon substrate by chemical vapor deposition. The observed electron-phonon cooling times vary from 160 ns at 2.70 K to 410 ns at 1.8 K following a T -2-dependence. The data are consistent with the values of τ eph previously reported for single-crystal boron-doped diamond films epitaxially grown on diamond substrate. Such a noticeable slow electron-phonon relaxation in boron-doped diamond, in combination with a high normal-state resistivity, confirms a potential of superconducting diamond for ultrasensitive superconducting bolometers.
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Elezov MS, Ozhegov RV, Goltsman GN, Makarov V. Development of the experimental setup for investigation of latching of superconducting single-photon detector caused by blinding attack on the quantum key distribution system. In: EPJ Web of Conferences. Vol 132.; 2017. 2.
Abstract: Recently bright-light control of the SSPD has been
demonstrated. This attack employed a “backdoor†in the detector biasing
scheme. Under bright-light illumination, SSPD becomes resistive and
remains “latched†in the resistive state even when the light is switched off.
While the SSPD is latched, Eve can simulate SSPD single-photon response
by sending strong light pulses, thus deceiving Bob. We developed the
experimental setup for investigation of a dependence on latching threshold
of SSPD on optical pulse length and peak power. By knowing latching
threshold it is possible to understand essential requirements for
development countermeasures against blinding attack on quantum key
distribution system with SSPDs.
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Vorobyov VV, Kazakov AY, Soshenko VV, Korneev AA, Shalaginov MY, Bolshedvorskii SV, et al. Superconducting detector for visible and near-infrared quantum emitters [Invited]. Opt Mater Express. 2017;7(2):513–26.
Abstract: Further development of quantum emitter based communication and sensing applications intrinsically depends on the availability of robust single-photon detectors. Here, we demonstrate a new generation of superconducting single-photon detectors specifically optimized for the 500–1100 nm wavelength range, which overlaps with the emission spectrum of many interesting solid-state atom-like systems, such as nitrogen-vacancy and silicon-vacancy centers in diamond. The fabricated detectors have a wide dynamic range (up to 350 million counts per second), low dark count rate (down to 0.1 counts per second), excellent jitter (62 ps), and the possibility of on-chip integration with a quantum emitter. In addition to performance characterization, we tested the detectors in real experimental conditions involving nanodiamond nitrogen-vacancy emitters enhanced by a hyperbolic metamaterial.
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Goltsman GN, Samartsev VV, Vinogradov EA, Naumov AV, Karimullin KR. New generation of superconducting nanowire single-photon detectors. In: EPJ Web of Conferences. Vol 103.; 2015. 01006 (1 to 2).
Abstract: We present an overview of recent results for new generation of infrared and optical superconducting nanowire single-photon detectors (SNSPDs) that has already demonstrated a performance that makes them devices-of-choice for many applications. SNSPDs provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, SNSPDs are also compatible with an integrated optical platform as a crucial requirement for applications in emerging quantum photonic technologies. By embedding SNSPDs in nanophotonic circuits we realize waveguide integrated single photon detectors which unite all desirable detector properties in a single device.
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Galin MA, Klushin AM, Kurin VV, Seliverstov SV, Finkel MI, Goltsman GN, et al. Towards local oscillators based on arrays of niobium Josephson junctions. Supercond Sci Technol. 2015;28(5):055002 (1 to 7).
Abstract: Various applications in the field of terahertz technology are in urgent need of compact, wide-tunable solid-state continuous wave radiation sources with a moderate power. However, satisfactory solutions for the THz frequency range are scarce yet. Here we report on coherent radiation from a large planar array of Josephson junctions (JJs) in the frequency range between 0.1 and 0.3 THz. The external resonator providing the synchronization of JJ array is identified as a straight fragment of a single-strip-line containing the junctions themselves. We demonstrate a prototype of the quasioptical heterodyne receiver with the JJ array as a local oscillator and a hot-electron bolometer mixer.
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Florya IN, Korneeva YP, Sidorova MV, Golikov AD, Gaiduchenko IA, Fedorov GE, et al. Energy relaxtation and hot spot formation in superconducting single photon detectors SSPDs. In: EPJ Web of Conferences. Vol 103.; 2015. 10004 (1 to 2).
Abstract: We have studied the mechanism of energy relaxation and resistive state formation after absorption of a single photon for different wavelengths and materials of single photon detectors. Our results are in good agreement with the hot spot model.
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