| 1. |
- Revin, L. S., et al.
(författare)
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Microwave photon detection by an Al Josephson junction
- 2020
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 11, s. 960-965
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Tidskriftsartikel (refereegranskat)abstract
- An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an anomalously large lifetime, not described by the Kramers' theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption.
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| 2. |
- Yablokov, Anton A., et al.
(författare)
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Resonant response drives sensitivity of Josephson escape detector
- 2021
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Ingår i: Chaos, Solitons and Fractals. - : Elsevier BV. - 0960-0779. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- The Josephson junction as a switching detector of weak signals is investigated in presence of noise in the frame of rotating pendulum model. The parameter range, where the detection can be more efficient, is found. It has been demonstrated, that with decrease of the signal power the double minima of the mean switching time and the standard deviation are transformed into a single minimum, which corresponds to interplay between noise suppression and resonant activation regimes. The resonant nature of escape allows to detect weak signals, whose amplitudes are weaker than the difference between critical current and bias current of a Josephson junction. With decrease of damping an efficient detection becomes possible even at subharmonics of the resonance frequency.
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| 3. |
- Pankratov, Andrey L., et al.
(författare)
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Approaching microwave photon sensitivity with Al Josephson junctions
- 2022
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 13, s. 582-589
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Tidskriftsartikel (refereegranskat)abstract
- Here, we experimentally test the applicability of an aluminium Josephson junction of a few micrometers size as a single photon counter in the microwave frequency range. We have measured the switching from the superconducting to the resistive state through the absorption of 10 GHz photons. The dependence of the switching probability on the signal power suggests that the switching is initiated by the simultaneous absorption of three and more photons, with a dark count time above 0.01 s.
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