| 1. |
- Snigirev, O., et al.
(författare)
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Superconducting Quantum Interference Filters as RF amplifiers
- 2007
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 17:2, s. 718-721
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Tidskriftsartikel (refereegranskat)abstract
- The superconducting Quantum Interference Filter (SQIF) is a new type of superconducting device which has been recently proposed for highly sensitive magnetometers for absolute magnetic field measurements. It benefits of very high voltage-to-field response, which is, in contrast conventional dc SQUIDs, not periodical. The SQIF can also be used as a radiofrequency amplifier in a similar way as the dc SQUID that can operate in a gigahertz frequency range. We designed a series type of SQIF amplifier that is compatible to conventional YBa2Cu3O7 (YBCO)technology on bicrystal substrates. We present analytical, numericaland scale modeling as well as first electrical measurementsresults at frequencies up to 10 GHz. The SQIF array consists of 50 loops with randomly distributed areas from 0.5 to 1.5 times of 3x30 m2. We also compared it to the regular array of conventional SQUIDs with the same loop areas. We have additional dc contacts to each 5-th SQUIDs and the SQIFs for control and comparison. Devices are fabricated using Josephson junctions with 3 m width formed in YBCO over 24/24 and 12/12 degrees grain boundaries in yttrium-stabilized zirconia (YSZ) bicrystal substrates.
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| 2. |
- Tarasov, Mikhail, 1954, et al.
(författare)
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Optical Response of a Cold-Electron Bolometer Array Integrated in a 345-GHz Cross-Slot Antenna
- 2011
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 21:6, s. 3635-3639
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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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| 3. |
- Tarasov, Mikhail, 1954, et al.
(författare)
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Power Load and Temperature Dependence of Cold-Electron Bolometer Optical Response at 350 GHz
- 2014
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 24:6, s. 1-
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Tidskriftsartikel (refereegranskat)abstract
- Cold-electron bolometers (CEBs) integrated with twin-slot antennas have been designed and fabricated. Optical response was measured at bath temperatures of 0.06 to 3 K using blackbody radiation source at temperatures of 3 to 15 K. The responsivity of 0.3 * 10(9) V/W was measured at 2.7-K blackbody temperature that is close to the temperature of the cosmic microwave background. Optical measurements indicate quasi-optical coupling efficiency of up to 60% at low phonon temperature and low signal level. Estimations for bolometer responsivity were made for practical range of bath temperatures and blackbody radiation temperatures. The estimated ultimate dark responsivity at 100-mK bath temperature can approach S-V = 10(10) V/W and reduces down to 1.1 * 10(8) V/W at 300 mK for a device with absorber volume of 5 * 10(-20) m(3).
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