|
|
Ozhegov RV, Gorshkov KN, Gol'tsman GN, Kinev NV, Koshelets VP. The stability of a terahertz receiver based on a superconducting integrated receiver. Supercond Sci Technol. 2011;24(3):035003.
Abstract: We present the results of stability testing of a terahertz radiometer based on a superconducting receiver with a SIS tunnel junction as the mixer and a flux-flow oscillator as the local oscillator. In the continuum mode, the receiver with a noise temperature of 95 K at 510 GHz measured over the intermediate frequency (IF) passband of 4-8 GHz offered a noise equivalent temperature difference of 10 ± 1 mK at an integration time of 1 s. We offer a method to significantly increase the integration time without the use of complex measurement equipment. The receiver observed a strong signal over a final detection bandwidth of 4 GHz and offered an Allan time of 5 s.
|
|
|
|
Seleznev VA, Tarkhov MA, Voronov BM, Milostnaya II, Lyakhno VY, Garbuz AS, et al. Deposition and characterization of few-nanometers-thick superconducting Mo-Re films. Supercond Sci Technol. 2008;21(11):115006 (1 to 6).
Abstract: We report on the fabrication and investigation of few-nanometers-thick superconducting molybdenum-rhenium (Mo-Re) films intended for use in nanowire single-photon superconducting detectors (SSPDs). Mo-Re films were deposited on sapphire substrates by DC magnetron sputtering of an Mo(60)-Re(40) alloy target in an atmosphere of argon. The films 2-10 nm thick had critical temperatures (Tc) from 5.6 to 9.7 K. HRTEM (high-resolution transmission electron microscopy) analysis showed that the films had a homogeneous structure. XPS (x-ray photoelectron spectroscopy) analysis showed the Mo to Re atom ratio to be 0.575/0.425, oxygen concentration to be 10%, and concentration of other elements to be 1%.
|
|
|
|
Lipatov A, Okunev O, Smirnov K, Chulkova G, Korneev A, Kouminov P, et al. An ultrafast NbN hot-electron single-photon detector for electronic applications. Supercond Sci Technol. 2002;15(12):1689–92.
Abstract: We present the latest generation of our superconducting single-photon detector (SPD), which can work from ultraviolet to mid-infrared optical radiation wavelengths. The detector combines a high speed of operation and low jitter with high quantum efficiency (QE) and very low dark count level. The technology enhancement allows us to produce ultrathin (3.5 nm thick) structures that demonstrate QE hundreds of times better, at 1.55 μm, than previous 10 nm thick SPDs. The best, 10 × 10 μm2, SPDs demonstrate QE up to 5% at 1.55 μm and up to 11% at 0.86 μm. The intrinsic detector QE, normalized to the film absorption coefficient, reaches 100% at bias currents above 0.9 Ic for photons with wavelengths shorter than 1.3 μm.
|
|
|
|
Il'in KS, Verevkin AA, Gol'tsman GN, Sobolewski R. Infrared hot-electron NbN superconducting photodetectors for imaging applications. Supercond Sci Technol. 1999;12(11):755–8.
Abstract: We report an effective quantum efficiency of 340, responsivity >200 A W-1 (>104 V W-1) and response time of 27±5 ps at temperatures close to the superconducting transition for NbN superconducting hot-electron photodetectors (HEPs) in the near-infrared and optical ranges. Our studies were performed on a few nm thick NbN films deposited on sapphire substrates and patterned into µm-size multibridge detector structures, incorporated into a coplanar transmission line. The time-resolved photoresponse was studied by means of subpicosecond electro-optic sampling with 100 fs wide laser pulses. The quantum efficiency and responsivity studies of our photodetectors were conducted using an amplitude-modulated infrared beam, fibre-optically coupled to the device. The observed picosecond response time and the very high efficiency and sensitivity of the NbN HEPs make them an excellent choice for infrared imaging photodetectors and input optical-to-electrical transducers for superconducting digital circuits.
|
|
|
|
Rönnung F, Cherednichenko S, Winkler D, Gol'tsman GN. A nanoscale YBCO mixer optically coupled with a bow tie antenna. Supercond Sci Technol. 1999;12(11):853–5.
Abstract: The bolometric response of YBa2Cu3O7-δ(YBCO) hot-electron bolometers (HEBs) to near-infrared radiation was studied. Devices were fabricated from a 50 nm thick film and had in-plane areas of 10 × 10 µm2, 2 × 0.2 µm2, 1 × 0.2µm2 and 0.5 × 0.2 µm2. We found that nonequilibrium phonons cool down more effectively for the bolometers with smaller area. For the smallest bolometer the bolometric component in the response is 10 dB less than for the largest one.
|
|
|
|
Danerud M, Winkler D, Lindgren M, Zorin M, Trifonov V, Karasik B, et al. A fast infrared detector based on patterned YBCO thin film. Supercond Sci Technol. 1994;7(5):321–3.
Abstract: Detectors for infrared radiation ( lambda =0.85 mu m) were made of 50 nm thick YBa2Cu3O7- delta films on LaAlO3 and MgO or 60 nm thick films on NdGaO3. Parallel strips (1 mu m wide by 20 mu m long) were patterned in the films and formed the active device. These devices were designed to detect short infrared laser pulses by electron heating. The detectors were current biased into the resistive and the normal states. The response was studied in direct pulse measurements as well as by amplitude modulation of a laser. The pulse measurements showed a fast picosecond response followed by a slower decay related to phonon escape through the film-substrate interface and heat diffusion in the substrate. The frequency spectra up to 10 GHz showed two slopes with a knee corresponding to the phonon escape time.
|
|
|
|
Gershenzon EM, Gol'tsman GN, Gogidze IG, Gusev YP, Elantiev AI, Karasik BS, et al. Millimeter and submillimeter wave range mixer based on electronic heating of superconducting films in the resistive state. Sov Supercond. 1990;3(10):1582–97.
|
|
|
|
Gershenzon EM, Gol'tsman GN, Kagane ML. Observation of free carrier resonances in p-type germanium at submillimeter wavelengths. Sov Phys Solid State. 1978;20(4):573–9.
Abstract: The spectrum of hole resonances in pure p-Ge for submillimetre in quantizing magnetic fields has been studied and identified. Measurements of photoconductivity spectra of p-Ge were made in the wave range lambda = 2-0.3 mm at temp. of 4.2-15 deg K in magnetic fields H up to 40 Measurements at various frequencies showed that the position of a series of characteristic resonances depends on the frequency of the illumination. This is in line with theoretical conclusions about the effective mass of the carriers increasing with rise in the magnetic field as a result of the interaction of the edge of the valency band with the split spin-orbital interaction of the sub 7 exp + band and the conduction band. The relative intensity of the quantum resonance lines of the free holes depends on the excitation conditions.
|
|
|
|
Gershenson EM, Gol'tsman GN, Elant'ev AI, Kagane ML, Multanovskii VV, Ptitsina NG. Use of submillimeter backward-wave tube spectroscopy in determination of the chemical nature and concentration of residual impurities in pure semiconductors. Sov Phys Semicond. 1983;17(8):908–13.
|
|
|
|
Gershenzon EM, Gol'tsman GN, Multanovskii VV, Ptitsina NG. Kinetics of electron and hole binding into excitons in germanium. Sov Phys JETP. 1983;57(2):369–76.
Abstract: The kinetics of binding of free carriers'into excitons under stationary and nonstationary conditions is studied by investigating the submillimeter photoconductivity of Ge in a wide range of temperatures and of excitation levels. It is shown that the absolute values and the temperature dependence of the binding cross section (o- T-'.' ) can be satisfactorily described by the cascade recombination theory. The value of o and its temperature dependence differ significantly from the cross sections, measured in the same manner, for capture by attracting small impurities. Under nonstationary conditions, just as in the case of recombination with shallow impurities, a signifi- cant role is played by the sticking of the carriers in highly excited states.
|
|
