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Sökning: WFRF:(Edelman Valerian)

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1.
  • Lemzyakov, S., et al. (författare)
  • Experimental study of a SINIS detector response time at 350 GHz signal frequency
  • 2018
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 969:1
  • Konferensbidrag (refereegranskat)abstract
    • Response time constant of a SINIS bolometer integrated in an annular ring antenna was measured at a bath temperature of 100 mK. Samples comprising superconducting aluminium electrodes and normal-metal Al/Fe strip connected to electrodes via tunnel junctions were fabricated on oxidized Si substrate using shadow evaporation. The bolometer was illuminated by a fast black-body radiation source through a band-pass filter centered at 350 GHz with a passband of 7 GHz. Radiation source is a thin NiCr film on sapphire substrate. For rectangular 10÷100 μs current pulse the radiation front edge was rather sharp due to low thermal capacitance of NiCr film and low thermal conductivity of substrate at temperatures in the range 1-4 K. The rise time of the response was ∼1-10 μs. This time presumably is limited by technical reasons: high dynamic resistance of series array of bolometers and capacitance of a long twisted pair wiring from SINIS bolometer to a room-Temperature amplifier.
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3.
  • Tarasov, Mikhail, et al. (författare)
  • Arrays of Annular Antennas With SINIS Bolometers
  • 2020
  • Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 30:3
  • Tidskriftsartikel (refereegranskat)abstract
    • For improving the dynamic range and sensitivity at high power load, we have integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) bolometers with a frequency selective surface (FSS)-based distributed absorber formed by a series and parallel array consisting of 25 annular antenna elements, each containing two SINIS bolometers. By using a design with 50 bolometers, we reduce incident power load on each bolometer, increase sensitivity and saturation power which is important for ground-based and balloon-borne telescopes with high background power loads. Our main detector pixel is optimized for a frequency band centered at 345GHz. The detectors are matched to incoming telescope beam by a back-to-back horn with a back reflector. Such a configuration improves both the efficiency and the bandwidth of the receiver. Measured voltage responsivity approaches 210(9) VW with an amplifier-limited voltage noise of 20nVHz(12), which corresponds to a NEP 10(-17) WHz(12). The linear voltage response for incoming power is observed for absorbed power of about 5 pW. The current responsivity for parallel array is 210(4) AW and the shot noise limited intrinsic noise equivalent power is NEP 510(-18)WHz(12). The noise equivalent temperature difference is NETD 100 KHz(12) at 2.7-K background radiation temperature.
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4.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Cryogenic Mimim and Simis Microwave Detectors
  • 2020
  • Ingår i: Proceedings - 2020 7th All-Russian Microwave Conference, RMC 2020. ; , s. 25-27
  • Konferensbidrag (refereegranskat)abstract
    • Microwave detectors of the Metal-Insulator-Metal-Insulator-Metal (MIMIM) structure and the Superconductor-Insulator-Metal-Insulator-Superconductor (SIMIS) structure have been designed, fabricated and investigated. The difference of such samples was in external electrodes, MIMIM uses copper external electrodes, while SIMIS uses aluminum. Identical in dimensions MIMIM and SIMIS samples have been fabricated and experimentally studied in the temperature range of 0.1-2.7 K. Voltage and current response were measured at 300 GHz external irradiation using Backward Wave Oscillator (BWO). According to our estimates, the MIMIM current responsivity is 1.1·103 A/W in the case of a photon response and 4·104 A/W in the case of a bolometric response. The estimated noise equivalent power is in the range 2.5·10 18 W/v Hz to 1.2·10-19 W/vHz.
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5.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Electrical and optical properties of a bolometer with a suspended absorber and tunneling-current thermometers
  • 2017
  • Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:24
  • Tidskriftsartikel (refereegranskat)abstract
    • We have developed a bolometer with a suspended normal-metal absorber connected to superconducting leads via tunneling barriers. Such an absorber has reduced heat losses to the substrate, which greatly increases the responsivity of the bolometer to over 10(9) V/W at 75 mK when measured by dc Joule heating of the absorber. For high-frequency experiments, the bolometers have been integrated in planar twin-slot and log-periodic antennas. At 300GHz and 100 mK, the bolometer demonstrates the voltage and current response of 3 x 10(8) V/W and 1.1 x 10(4) A/W, respectively, corresponding to the quantum efficiency of similar to 15 electrons per photon. An effective thermalization of electrons in the absorber favors the high quantum efficiency. We also report on how the in-plane-and transverse magnetic fields influence the device characteristics.
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6.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Fabrication of nis and sis nanojunctions with aluminum electrodes and studies of magnetic field influence on iv curves
  • 2021
  • Ingår i: Electronics (Switzerland). - : MDPI AG. - 2079-9292. ; 10:23
  • Tidskriftsartikel (refereegranskat)abstract
    • Samples of superconductor–insulator–superconductor (SIS) and normal metal–insulator– superconductor (NIS) junctions with superconducting aluminum of different thickness were fabricated and experimentally studied, starting from conventional shadow evaporation with a suspended resist bridge. We also developed alternative fabrication by magnetron sputtering with twostep direct e-beam patterning. We compared Al film grain size, surface roughness, resistivity deposited by thermal evaporation and magnetron sputtering. The best-quality NIS junctions with large superconducting electrodes approached a resistance R(0)/R(V2Δ) factor ratio of 1000 at 0.3 K and over 10,000 at 0.1 K. At 0.1 K, R(0) was determined completely by the Andreev current. The contribution of the single-electron current dominated at V > VΔ/2. The single-electron resistance extrapolated to V = 0 exceeded the resistance R(V2Δ) by 3 × 109. We measured the influence of the magnetic field on NIS junctions and described the mechanism of additional conductivity due to induced Abrikosov vortices. The modified shape of the SINIS bolometer IV curve was explained by Joule overheating via NIN (normal metal–insulator–normal metal) channels.
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7.
  • Tarasov, Michael, et al. (författare)
  • Non-Thermal Absorption and Quantum Efficiency of SINIS Bolometer
  • 2021
  • Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 31:5
  • Tidskriftsartikel (refereegranskat)abstract
    • We study mechanisms of absorption in two essentially different types of superconductor-insulator-normal metal-insulator-superconductor (SINIS) bolometers with absorber directly placed on Si wafer and with absorber suspended above the substrate. The figure of merit for quantum photon absorption is quantum efficiency equal to the number of detected electrons for one photon. The efficiency of absorption is dramatically dependent on phonon losses to substrate and electrodes, and electron energy losses to electrodes through tunnel junctions. The maximum quantum efficiency can approach n = hf/kT = 160 at f = 350 GHz T = 0.1 K, and current responsivity dI/dP = e/kT in quantum gain bolometer case, contrary to photon counter mode with quantum efficiency of n = 1 and responsivity dI/dP = e/hf. In experiments, we approach intrinsic quantum efficiency up to n = 80 electrons per photon in bolometer with suspended absorber, contrary to quantum efficiency of about one for absorber on the substrate. In the case of suspended Cu and Pd absorber, Kapitsa resistance protect from power leak to Al electrodes.
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8.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Nonthermal optical response of superconductor-insulator-normal metal-insulator-superconductor tunnel structures
  • 2014
  • Ingår i: Journal of Experimental and Theoretical Physics. - : Pleiades Publishing Ltd. - 1090-6509 .- 1063-7761. ; 119:1, s. 107-114
  • Tidskriftsartikel (refereegranskat)abstract
    • Bolometers, which are based on superconductor-insulator-normal metal-insulator-superconductor structures integrated into double slot antennas, are designed and fabricated. The change in the tunneling current in such structures during irradiation at a frequency of 330 GHz is experimentally studied at a temperature of about 0.1 K. It is found that, during irradiation, the energy distribution of electrons has a substantially nonequilibrium form, which differs from the Fermi distribution, and the main contribution to the addition to the tunneling current is made by the electrons that have no time to attain equilibrium within the electron system of the normal metal absorber. The characteristic electron and phonon relaxation times are estimated, and the estimates support the fact that the electron system is strongly nonequilibrium in the radiation field.
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9.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Optical response of a cold-electron bolometer array
  • 2010
  • Ingår i: JETP Letters. - 1090-6487 .- 0021-3640. ; 92:6, s. 416-420
  • Tidskriftsartikel (refereegranskat)abstract
    • A multielement bolometric receiver system has been developed to measure the power and polarization of radiation at a calculated frequency of 345 GHz. Arrays of ten series-parallel connected cold-electron bolometers have been pairwise integrated into orthogonal ports of a cross-slot antenna. Arrays are connected in parallel in the high-frequency input signal and in series in the output signal, which is measured at a low frequency, and in a dc bias. Such an array makes it possible to increase the output resistance by two orders of magnitude as compared to an individual bolometer under the same conditions of high-frequency matching and to optimize the matching with the JFET amplifier impedance up to dozens of megohms. Parallel connection ensures matching of the input signal to the cross-slot antenna with an impedance of 30 Omega on a massive silicon dielectric lens. At a temperature of 100 mK, a response to the thermal radiation of a thermal radiation source with an emissivity of 0.3, which covers the input aperture of the antenna and is heated to 3 K, is 25 mu V/K. Taking into account real noise, the optical fluctuation dc sensitivity is 5 mK, the estimated sensitivity corresponding to the noise of the amplifier is about 10(-4) K/Hz(1/2), and the noise-equivalent power is about (1-5) x 10(-17) W/Hz(1/2).
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10.
  • Tarasov, Mikhail, 1954, et al. (författare)
  • Optical Response of a Cold-Electron Bolometer Array Integrated in a 345-GHz Cross-Slot Antenna
  • 2011
  • Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 21:6, s. 3635-3639
  • Tidskriftsartikel (refereegranskat)abstract
    • Two series/parallel arrays of ten cold-electronbolometers with superconductor–insulator–normal tunnel junctionswere integrated in orthogonal ports of a cross-slot antenna.To increase the dynamic range of the receiver, all single bolometersin an array are connected in parallel for the microwavesignal by capacitive coupling. To increase the output response,bolometers are connected in series for dc bias. With the measuredvoltage-to-temperature response of 8.8 μV/mK, absorbervolume of 0.08 μm3, and output noise of about 10 nV/Hz1/2,we estimated the dark electrical noise equivalent power (NEP)as NEP = 6∗ 10−18 W/Hz1/2. The optical response down toNEP = 2∗ 10−17 W/Hz1/2 was measured using a hot/cold loadas a radiation source and a sample temperature down to 100 mK.The fluctuation sensitivity to the radiation source temperature is1.3 ∗ 10−4 K/Hz1/2. A dynamic range over 43 dB was measuredusing a backward-wave oscillator, a variable polarization gridattenuator, and cold filters/attenuators.
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