Santavicca, D. F., Reulet, B., Karasik, B. S., Pereverzev, S. V., Olaya, D., Gershenson, M. E., et al. (2010). Energy resolution of terahertz single-photon-sensitive bolometric detectors. Appl. Phys. Lett., 96(8), 083505-3.
Abstract: We report measurements of the energy resolution of ultrasensitive superconducting bolometric detectors. The device is a superconducting titanium nanobridge with niobium contacts. A fast microwave pulse is used to simulate a single higher-frequency photon, where the absorbed energy of the pulse is equal to the photon energy. This technique allows precise calibration of the input coupling and avoids problems with unwanted background photons. Present devices have an intrinsic full-width at half-maximum energy resolution of approximately 23 THz, near the predicted value due to intrinsic thermal fluctuation noise.
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Seki, T., Shibata, H., Takesue, H., Tokura, Y., & Imoto, N. (2010). Comparison of timing jitter between NbN superconducting single-photon detector and avalanche photodiode. Phys. C, 470(20), 1534–1537.
Abstract: We report the pulse-to-pulse timing jitter measurement of a niobium nitride (NbN) superconducting single-photon detector (SSPD) and an InGaAs avalanche photodiode (APD) at 1550-nm wavelength. A direct comparison of their timing jitter was performed by using the same experimental configuration to measure both detectors. The measured jitter of the SSPD and the APD are 75 and 84 ps at full-width at half-maximum (FWHM), and 138 and 384 ps at full-width at tenth-maximum (FWTM), respectively. The jitter of the SSPD remains small at FWTM while that of APD is wide. We also estimated the transmission distances and secure key generation rates for fiber-based quantum key distribution (QKD) which uses these detectors. The estimated transmission distances of the APD are 86 km and 107 km with respect to 1 ns and 100 ps time windows, respectively, and those of the SSPD are 125 km and 172 km with respect to 1 ns and 100 ps time windows, respectively. This estimation indicates the SSPDЃfs advantages for QKD compared to the APD.
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Жорес Алферов. (2010). Лекции на телеканале Культура. Полупроводниковая революция. Наука и общество..
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Karasik, B. S., & Cantor, R. (2010). Optical NEP in hot-electron nanobolometers. arXiv:1009.4676v1.
Abstract: For the first time, we have measured the optical noise equivalent power (NEP) in titanium (Ti) superconducting hot-electron nanobolometers (nano-HEBs). The bolometers were 2{\mu}mx1{\mu}mx20nm and 1{\mu}mx1{\mu}mx20nm planar antenna-coupled devices. The measurements were done at {\lambda} = 460 {\mu}m using a cryogenic black body radiation source delivering optical power from a fraction of a femtowatt to a few 100s of femtowatts. A record low NEP = 3x10^{-19} W/Hz^{1/2} at 50 mK has been achieved. This sensitivity meets the requirements for SAFARI instrument on the SPICA telescope. The ways for further improvement of the nano-HEB detector sensitivity are discussed.
Keywords: HEB, Ti, NEP, femtowatt, SAFARI, SPICA, 650 GHz, 0.65 THz, 460 um, twin slot antenna, SQUID readout
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Zhang, W., Khosropanah, P., Gao, J. R., Kollberg, E. L., Yngvesson, K. S., Bansal, T., et al. (2010). Quantum noise in a terahertz hot electron bolometer mixer. Appl. Phys. Lett., 96(11), 111113–(1–3).
Abstract: We have measured the noise temperature of a single, sensitive superconducting NbN hot electron bolometer (HEB) mixer in a frequency range from 1.6 to 5.3 THz, using a setup with all the key components in vacuum. By analyzing the measured receiver noise temperature using a quantum noise (QN) model for HEB mixers, we confirm the effect of QN. The QN is found to be responsible for about half of the receiver noise at the highest frequency in our measurements. The beta-factor (the quantum efficiency of the HEB) obtained experimentally agrees reasonably well with the calculated value.
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