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Shurakov A, Tong C-yu E, Grimes P, Blundell R, Golt'sman G. A microwave reflection readout scheme for hot electron bolometric direct detector. IEEE Trans THz Sci Technol. 2015;5:81–4.
Abstract: In this paper, we propose and present data from a fast THz detector based on the repurpose of hot electron bolometer mixers (HEB) fabricated from superconducting NbN thinfilm. This detector is essentially a traditional NbN bolometer element that operates under the influence of a microwave pump. The in-jected microwave power serves the dual purpose of enhancing the detector sensitivity and reading out the impedance changes of the device in response to incidentTHz radiation. We have measured an optical Noise Equivalent Power of 4 pW/ Hz for our detector at a bath temperature of 4.2 K. The measurement frequency was 0.83 THz and the modulation frequency was 1.48 kHz. The readout
scheme is versatile and facilitates both high-speed operation as well as multi-pixel applications.
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Korneeva Y, Florya I, Vdovichev S, Moshkova M, Simonov N, Kaurova N, et al. Comparison of hot-spot formation in NbN and MoN thin superconducting films after photon absorption. In: IEEE Transactions on Applied Superconductivity. Vol 27.; 2017. 5.
Abstract: In superconducting single-photon detectors SSPD
the efficiency of local suppression of superconductivity and hotspot
formation is controlled by diffusivity and electron-phonon
interaction time. Here we selected a material, 3.6-nm-thick MoNx
film, which features diffusivity close to those of NbN traditionally
used for SSPD fabrication, but with electron-phonon interaction
time an order of magnitude larger. In MoNx detectors we study
the dependence of detection efficiency on bias current, photon
energy, and strip width and compare it with NbN SSPD. We
observe non-linear current-energy dependence in MoNx SSPD
and more pronounced plateaus in dependences of detection
efficiency on bias current which we attribute to longer electronphonon
interaction time.
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Semenov AV, Devyatov IA, Ryabchun SA, Maslennikov SN, Maslennikova AS, Larionov PA, et al. Absorption of terahertz electromagnetic radiation in dirty superconducting film at arbitrary type of the spectral functions. Rus J Radio Electron. 2011;(10).
Abstract: A problem of absorption of high-frequency electromagnetic field in dirty superconductor is treated within Keldysh technic. Expression for the source term in the kinetic equation for quasiparticle distribution function is derived. The result is significant for deriving a consistent microscopic theory of superconducting detectors for terahertz frequency range, perspective detectors on kinetic inductance of current-biased superconducting strip and on Josephson inductance of tunnel.
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Ferrari S, Kovalyuk V, Hartmann W, Vetter A, Kahl O, Lee C, et al. Hot-spot relaxation time current dependence in niobium nitride waveguide-integrated superconducting nanowire single-photon detectors. Opt Express. 2017;25(8):8739–50.
Abstract: We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 +/- 1)ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions.
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Kahl O, Ferrari S, Kovalyuk V, Vetter A, Lewes-Malandrakis G, Nebel C, et al. Spectrally multiplexed single-photon detection with hybrid superconducting nanophotonic circuits. Optica. 2017;4(5):557–62.
Abstract: The detection of individual photons by superconducting nanowire single-photon detectors is an inherently binary mechanism, revealing either their absence or presence while concealing their spectral information. For multicolor imaging techniques, such as single-photon spectroscopy, fluorescence resonance energy transfer microscopy, and fluorescence correlation spectroscopy, wavelength discrimination is essential and mandates spectral separation prior to detection. Here, we adopt an approach borrowed from quantum photonic integration to realize a compact and scalable waveguide-integrated single-photon spectrometer capable of parallel detection on multiple wavelength channels, with temporal resolution below 50 ps and dark count rates below 10 Hz at 80% of the devices' critical current. We demonstrate multidetector devices for telecommunication and visible wavelengths, and showcase their performance by imaging silicon vacancy color centers in diamond nanoclusters. The fully integrated hybrid superconducting nanophotonic circuits enable simultaneous spectroscopy and lifetime mapping for correlative imaging and provide the ingredients for quantum wavelength-division multiplexing on a chip.
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