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Smirnov KV, Vachtomin YB, Ozhegov RV, Pentin IV, Slivinskaya EV, Korneev AA, et al. Fiber coupled single photon receivers based on superconducting detectors for quantum communications and quantum cryptography. In: Tománek P, Senderáková D, Hrabovský M, editors. Proc. SPIE. Vol 7138. Spie; 2008. 713827 (1 to 6).
Abstract: At present superconducting detectors become increasingly attractive for various practical applications. In this paper we present results on the depelopment of fiber coupled receiver systems for the registration of IR single photons, optimized for telecommunication and quantum-cryptography. These receiver systems were developed on the basis of superconducting single photon detectors (SSPD) of VIS and IR wavelength ranges. The core of the SSPD is a narrow ( 100 nm) and long ( 0,5 mm) strip in the form of a meander which is patterned from a 4-nm-thick NbN film (TC=10-11 K, jC= 5-7•106 A/cm2); the sensitive area dimensions are 10×10 μm2. The main problem to be solved while the receiver system development was optical coupling of a single-mode fiber (9 microns in diameter) with the SSPD sensitive area. Characteristics of the developed system at the optical input are as follows: quantum efficiency >10 % (at 1.3 μm), >4 % (at 1.55 μm); dark counts rate ≤1 s-1; duration of voltage pulse ≤5 ns; jitter ≤40 ps. The receiver systems have either one or two identical channels (for the case of carrying out correlation measurements) and are made as an insert in a helium storage Dewar.
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Sobolewski R, Zhang J, Slysz W, Pearlman A, Verevkin A, Lipatov A, et al. Ultrafast superconducting single-photon optical detectors. In: Spigulis J, Teteris J, Ozolinsh M, Lusis A, editors. Proc. SPIE. Vol 5123. SPIE; 2003. p. 1–11.
Abstract: We present a new class of single-photon devices for counting of both visible and infrared photons. Our superconducting single-photon detectors (SSPDs) are characterized by the intrinsic quantum efficiency (QE) reaching up to 100%, above 10 GHz counting rate, and negligible dark counts. The detection mechanism is based on the photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-wide superconducting stripe. The devices are fabricated from 3.5-nm-thick NbN films and operate at 4.2 K, well below the NbN superconducting transition temperature. Various continuous and pulsed laser sources in the wavelength range from 0.4 μm up to >3 μm were implemented in our experiments, enabling us to determine the detector QE in the photon-counting mode, response time, and jitter. For our best 3.5-nm-thick, 10×10 μm2-area devices, QE was found to reach almost 100% for any wavelength shorter than about 800 nm. For longer-wavelength (infrared) radiation, QE decreased exponentially with the photon wavelength increase. Time-resolved measurements of our SSPDs showed that the system-limited detector response pulse width was below 150 ps. The system jitter was measured to be 35 ps. In terms of the counting rate, jitter, and dark counts, the NbN SSPDs significantly outperform their semiconductor counterparts. Already identifeid and implemented applications of our devices range from noninvasive testing of semiconductor VLSI circuits to free-space quantum communications and quantum cryptography.
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Gershenzon EM, Goltsman GN, Orlov L. Investigation of population and ionization of donor excited states in Ge. In: Physics of Semiconductors. North-Holland Publishing Co.; 1976. p. 631–4.
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Blagosklonskaya LE, Gershenzon EM, Goltsman GN, Elantev AI. Effect of strong magnetic-field on spectrum of hydrogen-like admixtures in semiconductors. In: Izv. Akad. Nauk SSSR, Seriya Fizicheskaya. Vol 42. Mezhdunarodnaya Kniga 39 Dimitrova Ul., 113095 Moscow, Russia; 1978. p. 1231–4.
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Korneeva YP, Mikhailov MY, Pershin YP, Manova NN, Divochiy AV, Vakhtomin YB, et al. Superconducting single-photon detector made of MoSi film. Supercond Sci Technol. 2014;27(9):095012.
Abstract: We fabricated and characterized nanowire superconducting single-photon detectors made of 4 nm thick amorphous Mox Si1−x films. At 1.7 K the best devices exhibit a detection efficiency (DE) up to 18% at 1.2 $\mu {\rm m}$ wavelength of unpolarized light, a characteristic response time of about 6 ns and timing jitter of 120 ps. The DE was studied in wavelength range from 650 nm to 2500 nm. At wavelengths below 1200 nm these detectors reach their maximum DE limited by photon absorption in the thin MoSi film.
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