| 1. |
- Glushkov,, et al.
(författare)
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A broadband detector based on series YBCO grain boundary Josephson junctions
- 2022
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 13, s. 325-333
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Tidskriftsartikel (refereegranskat)abstract
- Modeling of a broadband receiving system based on a meander series of Josephson YBaCuO grain boundary junctions integrated into a log-periodic antenna was carried out. The electromagnetic properties of the system, namely amplitude-frequency characteristic, beam pattern, and fraction of the absorbed power in each Josephson junction were investigated. Based on the obtained results, a numerical simulation of one-dimensional arrays was carried out. The dc characteristics of the detector were calculated, that is, current-voltage characteristic, responsivity, noise, and noise-equivalent power (NEP) for a 250 GHz external signal. The optimal number of junctions to obtain the minimum NEP was found. The use of a series of junctions allows one to increase the responsivity by a factor of 2.5, the NEP value by a factor of 1.5, and the power dynamic range by a factor of 5. For typical YBaCuO Josephson junctions fabricated on a ZrYO bicrystal substrate by magnetron deposition, the following parameters were obtained at a temperature of 77 K: responsivity = 9 kV/W; NEP = 3.10(-13) W/Hz((1/2)); power dynamic range = 1.10(6).
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| 2. |
- 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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| 3. |
- Revin, Leonid S., et al.
(författare)
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Measurements of dichroic bow-tie antenna arrays with integrated cold-electron bolometers using YBCO oscillators
- 2024
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Ingår i: Beilstein Journal of Nanotechnology. - 2190-4286. ; 15, s. 26-36
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Tidskriftsartikel (refereegranskat)abstract
- We consider properties of dichroic antenna arrays on a silicon substrate with integrated cold-electron bolometers to detect radiation at frequencies of 210 and 240 GHz. This frequency range is widely used in cosmic microwave background experiments in space, balloon, and ground-based missions such as BICEP Array, LSPE, LiteBIRD, QUBIC, Simons Observatory, and AliCPT. As a direct radiation detector, we use cold-electron bolometers, which have high sensitivity and a wide operating frequency range, as well as immunity to spurious cosmic rays. Their other advantages are the compact size of the order of a few micrometers and the effect of direct electron cooling, which can improve sensitivity in typical closed-loop cycle 3He cryostats for space applications. We study a novel concept of cold-electron bolometers with two SIN tunnel junctions and one SN contact. The amplitude-frequency characteristics measured with YBCO Josephson Junction oscillators show narrow peaks at 205 GHz for the 210 GHz array and at 225 GHz for the 240 GHz array; the separation of these two frequency bands is clearly visible. The noise equivalent power level at an operating point in the current bias mode is 5 x 10-16 W/root Hz.
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| 4. |
- Agulo, Ian Jasper, 1974, et al.
(författare)
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An array of SIN tunnel junctions as a sensitive thermometer
- 2008
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Ingår i: Superconductor Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 21:1, s. 5-
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Tidskriftsartikel (refereegranskat)abstract
- We have fabricated and measured an array of superconductor-insulator-normal metal (SIN) tunnel junctions for the purpose of using it as a sensitive thermometer. An increase in the temperature responsivity of dV/dT similar to 5 mu V mK(-1) for ten junctions is observed from dV/dT similar to 1 mu V mK(-1) for a single junction. We then used such an array thermometer to measure the temperature stability of the Heliox AC-V cryogen-free refrigerator. We have been able to measure a temperature stability of +/- 250 mu K over a period of 8 h with a temperature resolution of +/- 100 mu K.
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| 5. |
- Agulo, Ian Jasper, 1974, et al.
(författare)
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Effective Electron Microrefrigeration by SIN Tunnel Junctions with Advanced Geometry of Electrodes and Normal Metal Traps
- 2004
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Ingår i: Nanotechnology. ; 15, s. S224-S228
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate effective electron cooling of the normal metal strip by superconductor-insulator-normal metal (SIN) tunnel junctions. The improvement was achieved by two methods: first by using an advanced geometry of the superconducting electrodes for more effective removal of the quasiparticles; and second, by adding a normal metal trap just near the cooling junctions. With simple cross geometry and without normal metal traps, the decrease in electron temperature is 56 mK. With the advanced geometry of the superconducting electrodes, the decrease in electron temperature is 129 mK. With the addition of the normal metal traps, the decrease in electron temperature is 197 mK.
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| 6. |
- Agulo, Ian Jasper, 1974, et al.
(författare)
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Responsivity and noise equivalent power of a single cold-electron bolometer
- 2021
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a single-pixel capacitively coupled Cold-Electron Bolometer (CEB) and characterized it in the current-biased regime. The most attractive feature of the CEB is effective electron self-cooling of the absorber, which leads to a lower bolometer noise and higher dynamic range. The bolometer responsivity was measured by determining the voltage response to an applied power through the absorber from a heating current, modulated at frequencies from 35 Hz to 2 kHz. The optimum responsivity of 1.5 × 10 V/W was measured at a modulation frequency of 35 Hz. The noise equivalent power (NEP) was subsequently obtained from the estimated bolometer noise voltage with respect to the measured bolometer responsivity. The NEP of better 2 × 10 W/Hz was obtained for modulation frequencies greater than 100 Hz. The background power and the bolometer time constant were also estimated from the experimental results. The photon-noise-limited operation of CEB will dominate for a signal power of 10 fW and higher at frequency 80 GHz and higher. 10 −18 1/2
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| 7. |
- Anghel, D. V., et al.
(författare)
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Cold-Electron Bolometer as a 1-cm-Wavelength Photon Counter
- 2020
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Ingår i: Physical Review Applied. - 2331-7019. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- We investigate theoretically the possibility of using the cold-electron bolometer (CEB) as a counter for 1-cm-wavelength (30-GHz) photons. To reduce the flux of photons from the environment that interact with the detector, the bath temperature is assumed to be below 50 mK. At such temperatures, the time interval between two subsequent photons of 30 GHz that hit the detector is more than 100 h, on average, for a frequency window of 1 MHz. Such temperatures allow the observation of the physically significant photons produced in rare events, such as axion conversion (or Primakoff conversion) in a magnetic field. We present the general formalism for the detector's response and noise, together with numerical calculations for proper experimental setups. We observe that the current-biased regime is favorable due to lower noise and allows for photon counting at least below 50 mK. For the experimental setups investigated here, the voltage-biased CEBs may also work as photon counters but with less accuracy and, eventually, may require smaller volumes of the normal-metal island.
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| 8. |
- Anghel,, et al.
(författare)
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Electromagnetic radiation detectors based on Josephson junctions: Effective Hamiltonian
- 2020
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 101:2
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically analyze two setups of low-energy single-photon counters based on Josephson junctions (JJs). For this, we propose two simple and general models based on the macroscopic quantum tunneling formalism (MQT). The first setup is similar to the photon counter based on the "cold-electron bolometer" (CEB), where the JJ replaces the CEB in the center of the superconducting antenna. In the second setup, the JJ is capacitively coupled to the antenna. We derive the Hamiltonians for the two setups, and we write the Schrodinger equations, taking into account both the antenna and the JJ. The quantum particles of the MQT models move in two-dimensional potential landscapes, which are parabolic along one direction and may have the form of a washboard potential along another direction. Such a potential landscape has a series of local minima, separated by saddle points. If the particle is prepared in the initial state in the metastable "ground state" of a local minimum, then the photon absorption causes it to jump into an excited state. If the excitation energy is bigger than the potential barrier seen by the quantum particle (the difference between the ground state and the saddle point), the photon is detected. The models are simple and allow us to do mostly analytical calculations. We show that the two setups are equivalent from the MQT point of view since one Hamiltonian can be transformed into the other by changes in variables. For typical values of the JJ and antenna parameters, the setups may work as counters of photons of wavelengths up to at least 1 cm. Dark count rates due to the phase particle tunneling directly from the ground state into the running state have also been evaluated.
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| 9. |
- Beiranvand, B., et al.
(författare)
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A distributed terahertz metasurface with cold-electron bolometers for cosmology missions
- 2021
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- We developed and tested a 2D periodic array of cold-electron bolometers arranged into a wideband frequency selective metasurface that absorbs more than 70% of the incident power in the frequency range 100–800 GHz. The array had 10 × 10 unit cells, each containing four bolometers incorporated into a ring. The chip with bolometers was mounted on the back side of the silicon lens without a back-reflector. Preliminary experiments demonstrated voltage responsivity as high as 10 V/W for the current-biased series array. Simulation of the noise performance shows realization of background noise-limited performance with NEP < NEP for the optical power load P > 15 pW. Results of numerical simulation made for the unit cell of the array are presented together with the equivalent diagram based on lumped network elements. The unit cell also was developed numerically to operate in two radiation modes.
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| 10. |
- Burmistrov, Eugeny, 1983, et al.
(författare)
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A planar picoamperemeter based on a superconducting quantum interferometer
- 2006
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Ingår i: J. Communications Technol. and Electron.. ; 51:11, s. 1319-1324
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Tidskriftsartikel (refereegranskat)abstract
- An optimized picoamperemeter based on a superconducting quantum interferometer device (SQUID) for a metal cold-electron bolometer is fabricated and experimentally studied. The intrinsic SQUID current noise caused by the input coil is estimated to be less than 1 pA/Hz@1/2. Owing to the application of modulation electronics, current sensitivity in the input coil reaches 5 pA/Hz@1/2 in the frequency band from 10 Hz to 10 kHz.
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