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Ryabchun S, Tong C-yu E, Blundell R, Kimberk R, Gol’tsman G. Stabilisation of a terahertz hot-electron bolometer mixer with microwave feedback control. In: Proc. 18th Int. Symp. Space Terahertz Technol.; 2007. p. 193–8.
Abstract: We report on implementation of microwave feedback control loop to stabilise the performance of an HEB mixer receiver. It is shown that the receiver sensitivity increases by a factor of 4 over a 16-minute scan, and the corresponding Allan time increases up to 10 seconds, as opposed to an open loop value of 1 second. Our experiments also demonstrate that the receiver sensitivity is limited by the intermediate frequency chain.
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Cherednichenko S, Rönnung F, Gol'tsman G, Kollberg E, Winkler D. YBa2Cu3O7−δ hot-electron bolometer mixer. Phys C: Supercond. 2000;341-348:2653–4.
Abstract: We present an investigation of hot-electron bolometric mixer based on YBa2Cu3O7−δ (YBCO) superconducting thin film. Mixer conversion loss, absorbed local oscillator power and intermediate frequency bandwidth was measured at the local oscillator frequency 600 GHz. The fabrication technique for nanoscale YBCO hot-electron bolometer (HEB) mixer integrated into planar antenna structure is described.
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Cherednichenko S, Rönnung F, Gol’tsman G, Kollberg E, Winkler D. YBa2Cu3O7-δ hot-electron bolometer mixer at 0.6 THz. In: Proc. 11th Int. Symp. Space Terahertz Technol.; 2000. p. 517–22.
Abstract: We present an investigation of hot-electron bolometric mixer based on a YBa 2 Cu 3 O 7-δ (YBCO) superconducting thin film. Mixer conversion loss of –46 dB, absorbed local oscillator power and intermediate frequency bandwidth were measured at the local oscillator frequency 0.6 THz. The fabrication technique for nanoscale YBCO hot-electron bolometer (HEB) mixer integrated with a planar antenna structure is described.
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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.
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Cherednichenko S, Ronnung F, Gol'tsman G, Gershenzon E, Winkler D. YBa2Cu3O7-δ hot-electron bolometer with submicron dimensions. In: Proc. 10th Int. Symp. Space Terahertz Technol.; 1999. p. 181–9.
Abstract: Photoresponse of YBa2Cu3O7-δ hot-electron bolometers to modulated near-infrared radiation was studied at a modulation .frequenc y var y ing from 0.2 MHz to 2 GHz. Bolometers were _fabricated from a 50 12 M thick film and had in-plane areas of 10x10 , um 2 . 2x0.2 s um', 1x0.2 p.m', and 0.5x0.2 jim. 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.
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Gousev YP, Semenov AD, Goghidze IG, Pechen EV, Varlashkin AV, Gol'tsman GN, et al. Current dependent noise in a YBa2Cu3O7-δ hot-electron bolometer. IEEE Trans Appl Supercond. 1997;7(2):3556–9.
Abstract: We investigated the output noise of a YBa2Cu3O7-δ (YBCO) superconducting hot-electron bolometer (HEB) in a large frequency range (10 kHz to 8 GHz); the bolometer either consisted of a structured 50 nm thick YBCO film on LaAlO/sub 3/ or a 30 nm thick film on a MgO substrate. We found that flicker noise dominated at low frequencies (below 1 MHz), while at higher frequencies Johnson noise and a current dependent noise were the main noise sources.
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Trifonov VA, Karasik BS, Zorin MA, Gol’tsman GN, Gershenzon EM, Lindgren M, et al. 9.6 μm wavelength mixing in a patterned YBa2Cu3O7‐δ thin film. Appl Phys Lett. 1996;68(10):1418–20.
Abstract: Hot‐electron bolometric (HEB) mixing of 9.6 μm infrared radiation from two lasers in high‐quality YBa2Cu3O7−δ (YBCO) patterned thin film has been demonstrated. A heterodyne measurement showed an intermediate frequency (IF) bandwidth of 18 GHz, limited by our measurement system. An intrinsic limit of 100 GHz is predicted. Between 0.1 and 1 GHz intermediate frequency, temperature fluctuations with an equivalent output noise temperature Tfl up to ∼150 K, contributed to the mixer noise while Johnson noise dominated above 1 GHz. The overall conversion loss at 77 K at low intermediate frequencies was measured to be ∼25 dB, of which 13 dB was due to the coupling loss. The HEB mixer is very promising for use in heterodyne receivers within the whole infrared range.
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Trifonov VA, Karasik BS, Zorin MA, Gol'tsman GN, Gershenzon EM, Lindgren M, et al. 9.6 μm wavelength mixing in a patterned YBa2Cu3O7-δ thin film. In: Proc. 7th Int. Symp. Space Terahertz Technol.; 1996. p. 337–48.
Abstract: Hot-electron bolometric (HEB) mixing of 9.6 gm infrared radiation from two lasers in high-quality YBa2Cu307_3 (YBCO) patterned thin film has been demonstrated. A heterodyne measurement showed an intermediate frequency (IF) bandwidth of 18 GHz, limited by our measurement system. An intrinsic limit of 100 GHz is predicted. Between 0.1 and 1 GHz intermediate frequency, temperature fluctuations with an equivalent output noise temperature Tfl up to -150 K, contributed to the mixer noise while Johnson noise dominated above 1 GHz. The overall conversion loss at 77 K at low intermediate frequencies was measured to be -25 dB, of which 13 dB was due to the coupling loss. The IIEB mixer is very promising for use in heterodyne receivers within the whole infrared range.
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Zorin M, Gol'tsman GN, Karasik BS, Elantev AI, Gershenzon EM, Lindgren M, et al. Optical mixing in thin YBa2Cu3O7-x films. IEEE Trans Appl Supercond. 1995;5(2):2431–4.
Abstract: High quality, j/sub c/ (77 K)>10/sup 6/ A/cm/sup 2/, epitaxial YBa2Cu3O7-x films of 50 nm thickness were patterned into ten parallel 1 /spl mu/m wide strips. The film structure was coupled to a single-mode fiber. Mixer response was obtained at 0.78 /spl mu/m using laser frequency modulation and an optical delay line. Using two semiconductor lasers at 1.55 /spl mu/m wavelength the beating signal was used to measure the photoresponse up to 18 GHz. Nonequilibrium photoresponse in the resistive state of the superconductor was observed. Bolometric response dominates up to 3 GHz, after which the nonequilibrium response is constant up to the frequency limit of our registration system. Using an electron heating model the influence of different thermal processes on the conversion loss has been analyzed. Ways of increasing the sensitivity are also discussed.
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Gershenzon EM, Gol’tsman GN, Gousev YP, Elant’ev AI, Semenov AD. Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films. IEEE Trans Magn. 1991;27(2):1317–20.
Abstract: A theory of an electron-heating mixer which makes it possible to calculate all the characteristics of the device is developed. It is shown that positive conversion gain is possible for such a mixer in the millimeter to near-infrared wavelength range. The dynamic range and the optimum heterodyne power can be selected from a very wide interval by varying the mixing element volume. Measurements made for Nb within the frequency range of 120-750 GHz confirm the theory. The conversion loss obtained at T=1.6 K and normalized to the element reaches 0.3 dB in the intermediate frequency band of 40 MHz; the possible noise temperature is 50 K. The estimation of noise temperature and output band for YBaCuO at T=77 yields 200 K and more than 10 GHz, respectively.
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