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Rosfjord KM, Yang JKW, Dauler EA, Kerman AJ, Vikas Anant, Voronov BM, et al. Nanowire Single-photon detector with an integrated optical cavity and anti-reflection coating. Opt Express. 2006;14(2):527–34.
Abstract: We have fabricated and tested superconducting single-photon detectors and demonstrated detection efficiencies of 57% at 1550-nm wavelength and 67% at 1064 nm. In addition to the peak detection efficiency, a median detection efficiency of 47.7% was measured over 132 devices at 1550 nm. These measurements were made at 1.8K, with each device biased to 97.5% of its critical current. The high detection efficiencies resulted from the addition of an optical cavity and anti-reflection coating to a nanowire photodetector, creating an integrated nanoelectrophotonic device with enhanced performance relative to the original device. Here, the testing apparatus and the fabrication process are presented. The detection efficiency of devices before and after the addition of optical elements is also reported.
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Marsili F, Najafi F, Herder C, Berggren KK. Electrothermal simulation of superconducting nanowire avalanche photodetectors. Appl Phys Lett. 2011;98(9):3.
Abstract: We developed an electrothermal model of NbN superconducting nanowire avalanche photodetectors (SNAPs) on sapphire substrates. SNAPs are single-photon detectors consisting of the parallel connection of N superconducting nanowires. We extrapolated the physical constants of the model from experimental data and we simulated the time evolution of the device resistance, temperature and current by solving two coupled electrical and thermal differential equations describing the nanowires. The predictions of the model were in good quantitative agreement with the experimental results.
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Marsili F, Najafi F, Dauler E, Bellei F, Hu X, Csete M, et al. Single-photon detectors based on ultranarrow superconducting nanowires. Nano Lett. 2011;11(5):2048–2053.
Abstract: We report efficient single-photon detection (η = 20% at 1550 nm wavelength) with ultranarrow (20 and 30 nm wide) superconducting nanowires, which were shown to be more robust to constrictions and more responsive to 1550 nm wavelength photons than standard superconducting nanowire single-photon detectors, based on 90 nm wide nanowires. We also improved our understanding of the physics of superconducting nanowire avalanche photodetectors, which we used to increase the signal-to-noise ratio of ultranarrow-nanowire detectors by a factor of 4, thus relaxing the requirements on the read-out circuitry and making the devices suitable for a broader range of applications.
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Hu X, Zhong T, White JE, Dauler EAN Faraz, Herder CH, Wong FNC, et al. Fiber-coupled nanowire photon counter at 1550 nm with 24% system detection efficiency. Opt Lett. 2009;34(23):3607–9.
Abstract: We developed a fiber-coupled superconducting nanowire single-photon detector system in a close-cycled cryocooler and achieved 24% and 22% system detection efficiencies at wavelengths of 1550 and 1315 nm, respectively. The maximum dark count rate was ~1000 counts/s.
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Kerman AJ, Yang JKW, Molnar RJ, Dauler EA, Berggren KK. Electrothermal feedback in superconducting nanowire single-photon detectors. Phys Rev B. 2009;79(10):4.
Abstract: We investigate the role of electrothermal feedback in the operation of superconducting nanowire single-photon detectors (SNSPDs). It is found that the desired mode of operation for SNSPDs is only achieved if this feedback is unstable, which happens naturally through the slow electrical response associated with their relatively large kinetic inductance. If this response is sped up in an effort to increase the device count rate, the electrothermal feedback becomes stable and results in an effect known as latching, where the device is locked in a resistive state and can no longer detect photons. We present a set of experiments which elucidate this effect and a simple model which quantitatively explains the results.
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