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Trifonov, A., Tong, C. - Y. E., Grimes, P., Lobanov, Y., Kaurova, N., Blundell, R., et al. (2017). Development of A Silicon Membrane-based Multi-pixel Hot Electron Bolometer Receiver. In IEEE Trans. Appl. Supercond. (Vol. 27, 6).
Abstract: We report on the development of a multi-pixel
Hot Electron Bolometer (HEB) receiver fabricated using
silicon membrane technology. The receiver comprises a
2 × 2 array of four HEB mixers, fabricated on a single
chip. The HEB mixer chip is based on a superconducting
NbN thin film deposited on top of the silicon-on-insulator
(SOI) substrate. The thicknesses of the device layer and
handling layer of the SOI substrate are 20 μm and 300 μm
respectively. The thickness of the device layer is chosen
such that it corresponds to a quarter-wave in silicon at
1.35 THz. The HEB mixer is integrated with a bow-tie
antenna structure, in turn designed for coupling to a
circular waveguide,
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Trifonov, A., Tong, C. - Y. E., Grimes, P., Lobanov, Y., Kaurova, N., Blundell, R., et al. (2017). Development of a silicon membrane-based multipixel hot electron bolometer receiver. IEEE Trans. Appl. Supercond., 27(4), 1–5.
Abstract: We report on the development of a multipixel hot electron bolometer (HEB) receiver fabricated using silicon membrane technology. The receiver comprises a 2 × 2 array of four HEB mixers, fabricated on a single chip. The HEB mixer chip is based on a superconducting NbN thin-film deposited on top of the silicon-on-insulator (SOI) substrate. The thicknesses of the device layer and handling layer of the SOI substrate are 20 and 300 μm, respectively. The thickness of the device layer is chosen such that it corresponds to a quarter-wave in silicon at 1.35 THz. The HEB mixer is integrated with a bow-tie antenna structure, in turn designed for coupling to a circular waveguide, fed by a monolithic drilled smooth-walled horn array.
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Trifonov, A., Tong, C. - Y. E., Lobanov, Y., Kaurova, N., Blundell, R., & Goltsman, G. (2017). Photon absorption near the gap frequency in a hot electron bolometer. IEEE Trans. Appl. Supercond., 27(4), 1–4.
Abstract: The superconducting energy gap is a fundamental characteristic of a superconducting film, which, together with the applied pump power and the biasing setup, defines the instantaneous resistive state of the Hot Electron Bolometer (HEB) mixer at any given bias point on the I-V curve. In this paper we report on a series of experiments, in which we subjected the HEB to radiation over a wide frequency range along with parallel microwave injection. We have observed three distinct regimes of operation of the HEB, depending on whether the radiation is above the gap frequency, far below it or close to it. These regimes are driven by the different patterns of photon absorption. The experiments have allowed us to derive the approximate gap frequency of the device under test as about 585 GHz. Microwave injection was used to probe the HEB impedance. Spontaneous switching between the superconducting (low resistive) state and a quasi-normal (high resistive) state was observed. The switching pattern depends on the particular regime of HEB operation and can assume a random pattern at pump frequencies below the gap to a regular relaxation oscillation running at a few MHz when pumped above the gap.
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Xiaolong Hu, Holzwarth, C. W., Masciarelli, D., Dauler, E. A., & Berggren, K. K. (2009). Efficiently coupling light to superconducting nanowire single-photon detectors. IEEE Trans. Appl. Supercond., 19(3), 336–340.
Abstract: We designed superconducting nanowire single-photon detectors (SNSPDs) integrated with silver optical antennae for free-space coupling and a dielectric waveguide for fiber coupling. According to our finite-element simulation, (1) for the free-space coupling, the absorptance of the NbN nanowire for TM-polarized photons at the wavelength of 1550 nm can be as high as 96% by adding silver optical antennae; (2) for the fiber coupling, the absorptance of the NbN nanowire for TE-like-polarized photons can reach 76% including coupling efficiency at the wavelength of 1550 nm by adding a silicon nitride waveguide and an inverse-taper coupler.
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Yagoubov, P., Kroug, M., Merkel, H., Kollberg, E., Schubert, J., Hubers, H. - W., et al. (1999). Heterodyne measurements of a NbN superconducting hot electron mixer at terahertz frequencies. IEEE Trans. Appl. Supercond., 9(2), 3757–3760.
Abstract: The performance of a NbN based phonon-cooled Hot Electron Bolometric (HEB) quasioptical mixer is investigated in the 0.65-3.12 THz frequency range. The device is made from a 3 nm thick NbN film on high resistivity Si and integrated with a planar spiral antenna on the same substrate. The in-plane dimensions of the bolometer strip are 0.2/spl times/2 /spl mu/m. The best results of the DSB noise temperature at 1.5 GHz IF frequency obtained with one device are: 1300 K at 650 GHz, 4700 K at 2.5 THz and 10000 K at 3.12 THz. The measurements were performed at 4.5 K ambient temperature. The amount of local oscillator (LO) power absorbed in the bolometer is about 100 nW. The mixer is linear to within 1 dB compression up to the signal level 10 dB below that of the LO. The intrinsic single sideband conversion gain measured at 650 GHz is -9 dB, the total conversion gain is -14 dB.
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Yamashita, T., Miki, S., Qiu, W., Fujiwara, M., Sasaki, M., & Wang, Z. (2010). Temperature dependent performances of superconducting nanowire single-photon detectors in an ultralow-temperature region. IEEE Trans. Appl. Supercond., 21(3), 336–339.
Abstract: We report on the performance of a fiber-coupled superconducting nanowire single-photon detector (SNSPD) from 4 K down to the ultralow temperature of 16 mK for a 1550 nm wave length. The system detection efficiency (DE) increased with de creasing the temperature and reached the considerably high value of 15% with a dark count rate less than 100 cps below 1.5 K, even without an optical cavity structure. We also observed saturation of the system DE in its bias current dependency at 16 mK, which indicates that the device DE of our SNSPD nearly reached intrinsic DE despite the device having a large active area of 20 μm × 20 μm. The dark count was finite even at 16 mK and the black body radiation becomes its dominant origin in the low temperatures for fiber-coupled devices.
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Yang, J. K. W., Kerman, A. J., Dauler, E. A., Anant, V., Rosfjord, K. M., & Berggren, K. K. (2007). Modeling the electrical and thermal response of superconducting nanowire single-photon detectors. IEEE Trans. Appl. Supercond., 17(2), 581–585.
Abstract: We modeled the response of superconducting nanowire single-photon detectors during a photodetection event, taking into consideration only the thermal and electrical properties of a superconducting NbN nanowire on a sapphire substrate. Our calculations suggest that heating which occurs after the formation of a photo-induced resistive barrier is responsible for the generation of a measurable voltage pulse. We compared this numerical result with experimental data of a voltage pulse from a slow device, i.e. large kinetic inductance, and obtained a good fit. Using this electro-thermal model, we estimated the temperature rise and the resistance buildup in the nanowire, and the return current at which the nanowire becomes superconducting again. We also show that the reset time of these photodetectors can be decreased by the addition of a series resistance and provide supporting experimental data. Finally we present preliminary results on a detector latching behavior that can also be explained using the electro-thermal model.
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Yang, J. K. W., Dauler, E., Ferri, A., Pearlman, A., Verevkin, A., Gol’tsman, G., et al. (2005). Fabrication development for nanowire GHz-counting-rate single-photon detectors. IEEE Trans. Appl. Supercond., 15(2), 626–630.
Abstract: We have developed a fabrication process for GHz-counting-rate, single-photon, high-detection-efficiency, NbN, nanowire detectors. We have demonstrated two processes for the device patterning, one based on the standard polymethylmethacrylate (PMMA) organic positive-tone electron-beam resist, and the other based on the newer hydrogen silsesquioxane (HSQ) negative-tone spin-on-glass resist. The HSQ-based process is simple and robust, providing high resolution and the prospect of high fill-factors. Initial testing results show superconductivity in the films, and suggest that the devices exhibit photosensitivity.
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Yang, J. K. W., Kerman, A. J., Dauler, E. A., Cord, B., Anant, V., Molnar, R. J., et al. (2009). Suppressed critical current in superconducting nanowire single-photon detectors with high fill-factors. IEEE Trans. Appl. Supercond., 19(3), 318–322.
Abstract: In this work we present a new fabrication process that enabled the fabrication of superconducting nanowire single photon detectors SNSPD with fill-factors as high as 88% with gaps between nanowires as small as 12 nm. This fabrication process combined high-resolution electron-beam lithography with photolithography. Although this work was motivated by the potential of increased detection efficiency with higher fill-factor devices, test results showed an unexpected systematic suppression in device critical currents with increasing fill-factor.
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Zhang, J., Slysz, W., Verevkin, A., Okunev, O., Chulkova, G., Korneev, A., et al. (2003). Response time characterization of NbN superconducting single-photon detectors. IEEE Trans. Appl. Supercond., 13(2), 180–183.
Abstract: We report our time-resolved measurements of NbN-based superconducting single-photon detectors. The structures are meander-type, 10-nm thick, and 200-nm wide stripes and were operated at 4.2 K. We have shown that the NbN devices can count single-photon pulses with below 100-ps time resolution. The response signal pulse width was about 150 ps, and the system jitter was measured to be 35 ps.
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