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Goltsman G, Korneev A, Divochiy A, Minaeva O, Tarkhov M, Kaurova N, et al. Ultrafast superconducting single-photon detector. J Modern Opt. 2009;56(15):1670–80.
Abstract: The state-of-the-art of the NbN nanowire superconducting single-photon detector technology (SSPD) is presented. The SSPDs exhibit excellent performance at 2 K temperature: 30% quantum efficiency from visible to infrared, negligible dark count rate, single-photon sensitivity up to 5.6 µm. The recent achievements in the development of GHz counting rate devices with photon-number resolving capability is presented.
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Nasr MB, Minaeva O, Goltsman GN, Sergienko AV, Saleh BE, Teich MC. Submicron axial resolution in an ultrabroadband two-photon interferometer using superconducting single-photon detectors. Opt Express. 2008;16(19):15104–8.
Abstract: We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion in a quasi-phase-matched nonlinear grating that has a linearly chirped poling period. Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of approximately 5.7 fsec. This FWHM corresponds to a quantum optical coherence tomography (QOCT) axial resolution of 0.85 µm. Our results indicate that a high flux of nonoverlapping biphotons may be generated, as required in many applications of nonclassical light.
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Gol'tsman G, Minaeva O, Korneev A, Tarkhov M, Rubtsova I, Divochiy A, et al. Middle-infrared to visible-light ultrafast superconducting single-photon detectors. IEEE Trans Appl Supercond. 2007;17(2):246–51.
Abstract: We present an overview of the state-of-the-art of NbN superconducting single-photon detectors (SSPDs). Our devices exhibit quantum efficiency (QE) of up to 30% in near-infrared wavelength and 0.4% at 5 mum, with a dark-count rate that can be as low as 10 -4 s -1 . The SSPD structures integrated with lambda/4 microcavities achieve a QE of 60% at telecommunication, 1550-nm wavelength. We have also developed a new generation of SSPDs that possess the QE of large-active-area devices, but, simultaneously, are characterized by low kinetic inductance that allows achieving short response times and the GHz-counting rate with picosecond timing jitter. The improvements presented in the SSPD development, such as fiber-coupled SSPDs, make our detectors most attractive for high-speed quantum communications and quantum computing.
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Kitaygorsky J, Komissarov I, Jukna A, Pan D, Minaeva O, Kaurova N, et al. Dark counts in nanostructured nbn superconducting single-photon detectors and bridges. IEEE Trans Appl Supercond. 2007;17(2):275–8.
Abstract: We present our studies on dark counts, observed as transient voltage pulses, in current-biased NbN superconducting single-photon detectors (SSPDs), as well as in ultrathin (~4 nm), submicrometer-width (100 to 500 nm) NbN nanobridges. The duration of these spontaneous voltage pulses varied from 250 ps to 5 ns, depending on the device geometry, with the longest pulses observed in the large kinetic-inductance SSPD structures. Dark counts were measured while the devices were completely isolated (shielded by a metallic enclosure) from the outside world, in a temperature range between 1.5 and 6 K. Evidence shows that in our two-dimensional structures the dark counts are due to the depairing of vortex-antivortex pairs caused by the applied bias current. Our results shed some light on the vortex dynamics in 2D superconductors and, from the applied point of view, on intrinsic performance of nanostructured SSPDs.
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Korneev A, Matvienko V, Minaeva O, Milostnaya I, Rubtsova I, Chulkova G, et al. Quantum efficiency and noise equivalent power of nanostructured, NbN, single-photon detectors in the wavelength range from visible to infrared. IEEE Trans Appl Supercond. 2005;15(2):571–4.
Abstract: We present our studies on the quantum efficiency (QE) and the noise equivalent power (NEP) of the latest-generation, nanostructured, superconducting, single-photon detectors (SSPDs) in the wavelength range from 0.5 to 5.6 /spl mu/m, operated at temperatures in the 2.0- to 4.2-K range. Our detectors are designed as 4-nm-thick and 100-nm-wide NbN meander-shaped stripes, patterned by electron-beam lithography and cover a 10/spl times/10-/spl mu/m/sup 2/ active area. The best-achieved QE at 2.0 K for 1.55-/spl mu/m photons is 17%, and QE for 1.3-/spl mu/m infrared photons reaches its saturation value of /spl sim/30%. The SSPD NEP at 2.0 K is as low as 5/spl times/10/sup -21/ W/Hz/sup -1/2/. Our nanostructured SSPDs, operated at 2.0 K, significantly outperform their semiconducting counterparts, and, together with their GHz counting rate and picosecond timing jitter, they are devices-of-choice for practical quantum key distribution systems and free-space (even interplanetary) quantum optical communications.
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