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Gershenzon EM, Gershenzon ME, Goltsman GN, Semenov AD, Sergeev AV. Wide-band highspeed Nb and YBaCuO detectors. IEEE Trans Magn. 1991;27(2):2836–9.
Abstract: The physical limitations on the response time and the nature of nonequilibrium detection of radiation were investigated for Nb and YBCO film in a wide spectral range from millimeter to near-infrared wavelengths. In the case of ideal heat removal from the film, the detection mechanism is connected with an electron heating effect which is not selective over a wide spectral interval. For Nb, the dependence of the response time on the electron mean free path l and temperature T is tau varies as T/sup -2/l/sup -1/. The values of detectivity D* and tau are 3*10/sup 11/ W/sup -1/ Hz/sup 1/2/ cm and 5*10/sup -9/ s at T=1.6 K, respectively. For YBCO film the tau value of 1-2 ps at T=77 K was obtained; the NEP value of 3*10/sup -11/ W-Hz/sup -1/2/ can be obtained at T=77 K in the case of the optimal film matching to the radiation.
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Gershenzon EM, Gol’tsman GN, Semenov AD, Sergeev AV. Mechanism of picosecond response of granular YBaCuO films to electromagnetic radiation. IEEE Trans Magn. 1991;27(2):1321–4.
Abstract: Ultrafast mechanisms of radiation detection in granular YBaCuO films are studied in the wide wavelength range from millimeter waves to near infrared. With an increase in radiation frequency, the Josephson detection at the grain-boundary weak links is replaced by electron heating into the grains. This change occurs in the submillimeter wavelength range. The electron-phonon relaxation time tau /sub eph/ is determined from direct measurements, quasi-stationary electron heating measurements, and the frequency dependence of the current at which maximum voltage shift is observed. The temperature dependence of tau /sub eph/ at T<or=40 K was found to be tau /sub eph/ approximately T/sup -1/. The results show that detectors with a response time of a few picoseconds at nitrogen temperature are attainable.
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Shurakov A, Tong C-yu E, Grimes P, Blundell R, Golt'sman G. A microwave reflection readout scheme for hot electron bolometric direct detector. IEEE Trans THz Sci Technol. 2015;5:81–4.
Abstract: In this paper, we propose and present data from a fast THz detector based on the repurpose of hot electron bolometer mixers (HEB) fabricated from superconducting NbN thinfilm. This detector is essentially a traditional NbN bolometer element that operates under the influence of a microwave pump. The in-jected microwave power serves the dual purpose of enhancing the detector sensitivity and reading out the impedance changes of the device in response to incidentTHz radiation. We have measured an optical Noise Equivalent Power of 4 pW/ Hz for our detector at a bath temperature of 4.2 K. The measurement frequency was 0.83 THz and the modulation frequency was 1.48 kHz. The readout
scheme is versatile and facilitates both high-speed operation as well as multi-pixel applications.
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Korneeva Y, Florya I, Vdovichev S, Moshkova M, Simonov N, Kaurova N, et al. Comparison of hot-spot formation in NbN and MoN thin superconducting films after photon absorption. In: IEEE Transactions on Applied Superconductivity. Vol 27.; 2017. 5.
Abstract: In superconducting single-photon detectors SSPD
the efficiency of local suppression of superconductivity and hotspot
formation is controlled by diffusivity and electron-phonon
interaction time. Here we selected a material, 3.6-nm-thick MoNx
film, which features diffusivity close to those of NbN traditionally
used for SSPD fabrication, but with electron-phonon interaction
time an order of magnitude larger. In MoNx detectors we study
the dependence of detection efficiency on bias current, photon
energy, and strip width and compare it with NbN SSPD. We
observe non-linear current-energy dependence in MoNx SSPD
and more pronounced plateaus in dependences of detection
efficiency on bias current which we attribute to longer electronphonon
interaction time.
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González FJ, Boreman GD. Comparison of dipole, bowtie, spiral and log-periodic IR antennas. Inf Phys & Technol. 2005;46(5):418–28.
Abstract: Antenna-coupled microbolometers use planar lithographic antennas to couple infrared radiation into a bolometer with sub-micron dimensions. In this paper four different types of infrared antennas were fabricated on thin grounded-substrates and coupled to microbolometers. Dipole, bowtie, spiral and log-periodic IR antenna-coupled detectors were measured at 10.6 μm and their performance compared. A new method to calculate the radiation efficiency based on the spatial and angular response of infrared antennas is presented and used to evaluate their performance. The calculated radiation efficiency for the dipole, bowtie, spiral and log-periodic IR antennas was 20%, 37%, 25% and 46% respectively. A dipole-length study was performed and shows that the quasistatic value of the effective permittivity accurately describes the incident wavelength in the substrate at infrared frequencies for antennas on a thin substrate.
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