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Hoevers, H. F. C., Bento, A. C., Bruijn, M. P., Gottardi, L., Korevaar, M. A. N., Mels, W. A., et al. (2000). Thermal fluctuation noise in a voltage biased superconducting transition edge thermometer. Appl. Phys. Lett., 77(26), 4421–4424.
Abstract: The current noise at the output of a microcalorimeter with a voltage biased superconducting transition edge thermometer is studied in detail. In addition to the two well-known noise sources: thermal fluctuation noise from the heat link to the bath and Johnson noise from the resistive thermometer, a third noise source strongly correlated with the steepness of the thermometer is required to fit the measured noise spectra. Thermal fluctuation noise, originating in the thermometer itself, fully explains the additional noise. A simple model provides quantitative agreement between the observed and calculated noise spectra for all bias points in the superconducting transition.
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Burke, P. J., Schoelkopf, R. J., Prober, D. E., Skalare, A., Karasik, B. S., Gaidis, M. C., et al. (1998). Spectrum of thermal fluctuation noise in diffusion and phonon cooled hot-electron mixers. Appl. Phys. Lett., 72(12), 1516–1518.
Abstract: A systematic study of the intermediate frequency noise bandwidth of Nb thin-film superconducting hot-electron bolometers is presented. We have measured the spectrum of the output noise as well as the conversion efficiency over a very broad intermediate frequency range (from 0.1 to 7.5 GHz) for devices varying in length from 0.08 μm to 3 μm. Local oscillator and rf signals from 8 to 40 GHz were used. For a device of a given length, the spectrum of the output noise and the conversion efficiency behave similarly for intermediate frequencies less than the gain bandwidth, in accordance with a simple thermal model for both the mixing and thermal fluctuation noise. For higher intermediate frequencies the conversion efficiency decreases; in contrast, the noise decreases but has a second contribution which dominates at higher frequency. The noise bandwidth is larger than the gain bandwidth, and the mixer noise is low, between 120 and 530 K (double side band).
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Sprengers, J. P., Gaggero, A., Sahin, D., Jahanmirinejad, S., Frucci, G., Mattioli, F., et al. (2011). Waveguide superconducting single-photon detectors for integrated quantum photonic circuits. Appl. Phys. Lett., 99(18), 181110(1–3).
Abstract: The monolithic integration of single-photon sources, passive optical circuits, and single-photon detectors enables complex and scalable quantum photonic integrated circuits, for application in linear-optics quantum computing and quantum communications. Here, we demonstrate a key component of such a circuit, a waveguide single-photon detector. Our detectors, based on superconducting nanowires on GaAs ridge waveguides, provide high efficiency (~0%) at telecom wavelengths, high timing accuracy (~0 ps), and response time in the ns range and are fully compatible with the integration of single-photon sources, passive networks, and modulators.
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Inderbitzin, K., Engel, A., Schilling, A., Il'in, K., & Siegel, M. (2012). An ultra-fast superconducting Nb nanowire single-photon detector for soft x-rays. Appl. Phys. Lett., 101.
Abstract: Although superconducting nanowire single-photon detectors (SNSPDs) are well studied regarding the
detection of infrared/optical photons and keV-molecules, no studies on continuous x-ray photon
counting by thick-film detectors have been reported so far. We fabricated a 100 nm thick niobium
x-ray SNSPD (an X-SNSPD) and studied its detection capability of photons with keV-energies in
continuous mode. The detector is capable to detect photons even at reduced bias currents of 0.4%,
which is in sharp contrast to optical thin-film SNSPDs. No dark counts were recorded in extended
measurement periods. Strikingly, the signal amplitude distribution depends significantly on the photon
energy spectrum.VC
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Kataoka, T., Kajikawa, K., Kitagawa, J., Kadoya, Y., & Takemura, Y. (2010). Improved sensitivity of terahertz detection by GaAs photoconductive antennas excited at 1560 nm. Appl. Phys. Lett., 97, 201110 (1–3).
Abstract: The terahertz detection by photoconductive antennas (PCAs) based on low-temperature grown (LTG) GaAs with 1.5 μm pulse excitation was revisited. We found that the detection efficiency can be improved by a factor of 10 (20 dB) by reducing the excitation spot size and the gap length of the PCA, maintaining the low noise feature of the PCA on LTG GaAs. As a result, the signal-to-noise ratio higher than 50 dB was obtained at a reasonable incident power of 9.5 mW, suggesting that the scheme is promising for the detection of terahertz waves in practical time domain systems.
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Gao, J. R., Hovenier, J. N., Yang, Z. Q., Baselmans, J. J. A., Baryshev, A., Hajenius, M., et al. (2005). Terahertz heterodyne receiver based on a quantum cascade laser and a superconducting bolometer. Appl. Phys. Lett., 86, 244104 (1 to 3).
Abstract: We report the first demonstration of an all solid-stateheterodyne receiver that can be used for high-resolution spectroscopy above 2THz suitable for space-based observatories. The receiver uses a NbN superconducting hot-electron bolometer as mixer and a quantum cascade laser operating at 2.8THz as local oscillator. We measure a double sideband receiver noise temperature of 1400K at 2.8THz and 4.2K, and find that the free-running QCL has sufficient power stability for a practical receiver, demonstrating an unprecedented combination of sensitivity and stability.
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Gousev, Y. P., Semenov, A. D., Pechen, E. V., Varlashkin, A. V., Nebosis, R. S., & Renk K. F. (1996). Coupling of terahertz radiation to a high-Т(с) superconducting hot electron bolometer mixer. Appl. Phys. Lett.,, 69, 691–693.
Abstract: We report on efficient coupling of THz radiation to a high-T(c) superconducting hot electron bolometer that is suitable for heterodyne detection. Our quasioptical system consisted of a planar self-complementary spiral antenna on a dielectric substrate clamped to an extended hyperhemispherical lens. The antenna was integrated into a co-planar line for broadband intermediate frequency matching. Measurements in the homodyne regime at a frequency of 2.5 THz showed a radiation pattern with a beam width of 1° and a coupling efficiency of 0.1. We measured, at an intermediate frequency of 1.5 GHz, an output noise temperature of'160 K and estimated for the device, operated in the heterodyne regime, a system noise temperature of 30 000 K. We also discuss possibilities of significant improvement of the sensitivity.
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