| Autor: |
Ovsyannikov, Germady A., Borisenko, Igor V., Constantinian, Karen Y., Kislinski, Yulii V., Hakhoumian, Arsen A., Pogosyan, Nubar G., Zakaryan, Tigran, Pedersen, Niels F., Mygind, Jesper, Uzunoglu, Nikolaos, Karagianni, Evangelia |
| Předmět: |
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| Zdroj: |
IEEE Transactions on Applied Superconductivity; Jun2005 Part 1 of 3, Vol. 15 Issue 2, p533-336, 4p |
| Abstrakt: |
Detectors made from superconducting cuprate YBa2Cu3Ox bicrystal Josephson junctions (BJJs) on sapphire and NdGaO3 substrates' have been fabricated and characterized in the frequency band 200-900 GHz. Junctions on sapphire substrates had a normal state resistance RN ≈ 15 - 60Ω, and ICRN product up to 2.5 mV at T = 4.2 K. Junctions on NdGaO3 substrates had lower RN = 1 - 5 Ω and ICRN = 0.4-0.9 mV at T = 77 K. Three types of detecting devices have been investigated in both the broadband and the frequency-selective detection modes. One type was patterned with log-periodic antenna, and two others with Pt-metal double-slot antenna designed for a central frequency f = 300 GHz and f = 400 GHz, respectively. Measurements at f = 320 GHz of the reception bandwidth Δf for a device with double-slot antenna gave a quality factor Q = f/Δf ≈ 10. A low-noise cooled 1-2 GHz bandwidth amplifier enables a better sensitivity in the self-pumping frequency mixing mode, avoiding the 1/f noise. The dependence of the spectral density of noise on voltage was compared to the data for the Josephson emission linewidth obtained by the selective detector response method. Also discussed are measurements at 500 GHz of the NEP values carried out at different experimental conditions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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