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Author Huebers, Heinz-Wilhelm; Pavlov, S.; Semenov, A.; Köhler, R.; Mahler, L.; Tredicucci, A.; Beere, H.; Ritchie, D.; Linfield, E.
Title Terahertz quantum cascade laser as local oscillator in a heterodyne receiver Type Journal Article
Year 2005 Publication Optics Express Abbreviated Journal
Volume 13 Issue 15 Pages 5890-5896
Keywords (up) QCL heterodyne, 6 mW at 2.5 THz, HEB mixer, terahertz
Abstract Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same result as with a gas laser as local oscillator.
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Notes Approved no
Call Number Serial 627
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Author Semenov, A.; Goltsman, G.; Korneev, A.
Title Quantum detection by current carrying superconducting film Type Journal Article
Year 2001 Publication Phys. C: Supercond. Abbreviated Journal Phys. C: Supercond.
Volume 351 Issue 4 Pages 349-356
Keywords (up) quantum detection, phase slip centers, quasiparticle diffusion
Abstract We describe a novel quantum detection mechanism in the superconducting film carrying supercurrent. The mechanism incorporates growing normal domain and breaking of superconductivity by the bias current. A single photon absorbed in the film creates transient normal spot that causes redistribution of the current and, consequently, increase of the current density in superconducting areas. When the current density exceeds the critical value, the film switches into resistive state and generates the voltage pulse. Analysis shows that a submicron-wide film of conventional low temperature superconductor operated in liquid helium may detect single far-infrared photon. The amplitude and duration of the voltage pulse are in the millivolt and picosecond range, respectively. The quantitative model is presented that allows simulation of the detector utilizing this detection mechanism.
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Series Volume Series Issue Edition
ISSN 0921-4534 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 507
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Author Sidorova, M.; Semenov, A.; Hübers, H.-W.; Kuzmin, A.; Doerner, S.; Ilin, K.; Siegel, M.; Charaev, I.; Vodolazov, D.
Title Timing jitter in photon detection by straight superconducting nanowires: Effect of magnetic field and photon flux Type Journal Article
Year 2018 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 98 Issue 13 Pages 134504 (1 to 14)
Keywords (up) SNSPD, NbN namowires
Abstract We studied the effects of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance times of photon counts exhibits Gaussian shape at small times and an exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from the discrete quantum detection regime to the uniform bolometric regime that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between standard deviations of Gaussian parts of distributions for these two regimes provides the measure for the strength of electron-number fluctuations; it increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
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ISSN 2469-9950 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1842
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Author Murphy, A.; Semenov, A.; Korneev, A.; Korneeva, Y.; Gol'tsman, G.; Bezryadin, A.
Title Three temperature regimes in superconducting photon detectors: quantum, thermal and multiple phase-slips as generators of dark counts Type Journal Article
Year 2015 Publication Sci. Rep. Abbreviated Journal Sci. Rep.
Volume 5 Issue Pages 10174 (1 to 10)
Keywords (up) SPD, SSPD, SNSPD
Abstract We perform measurements of the switching current distributions of three w approximately 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter of the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors. At the highest temperatures the system enters a multiple phase-slip regime. In this range single phase-slips are unable to produce dark counts and the fluctuations in the switching current are reduced.
Address Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
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Notes PMID:25988591; PMCID:PMC4437302 Approved no
Call Number Serial 1344
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Author Semenov, A.; Hübers, H.-W.; Engel, A.; Gol’tsman, G.
Title Superconducting quantum detector for far infrared astronomy Type Conference Article
Year 2002 Publication Far-IR, Sub-mm & MM Detector Technology Workshop Abbreviated Journal Far-IR, Sub-mm & MM Detector Technology Workshop
Volume Issue Pages 3-49
Keywords (up) SQD
Abstract We present the concept of the superconducting quantum detector for astronomy. Response to a single absorbed photon appears due to successive formation of a normal spot and phase-slip-centres in a narrow strip carrying sub-critical supercurrent. The detector simultaneously has a moderate energy resolution and a variable cut-off wavelength depending on both the material used and operation conditions. We simulated performance of the background-limited direct detector having the 100-micrometer cut-off wavelength. Low dark count rate will allow to realise 10-21 W Hz-1/2 noise equivalent power at 4 K background radiation. The detection mechanism provides a moderate 1/20 energy resolution at 50-micrometer wavelength.
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Publisher NASA Place of Publication Editor Wolf, J.; Farhoomand, J.; McCreight, C.R.
Language Summary Language Original Title
Series Editor Series Title NASA CP Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Volume: 211408 Approved no
Call Number Serial 1538
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