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Pernice, W., Schuck, C., Minaeva, O., Li, M., Goltsman, G. N., Sergienko, A. V., et al. (2012). High speed and high efficiency travelling wave single-photon detectors embedded in nanophotonic circuits (Vol. 1108.5299). arXiv:1108.5299v2 [physics.optics]. Retrieved July 5, 2024, from https://arxiv.org/abs/1108.5299v2
Abstract: Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics.
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Vercruyssen, N., Verhagen, T. G. A., Flokstra, M. G., Pekola, J. P., & Klapwijk, T. M. (2012). Evanescent states and nonequilibrium in driven superconducting nanowires. Phys. Rev. B, 85, 224503(1–10).
Abstract: We study the nonlinear response of current transport in a superconducting diffusive nanowire between normal reservoirs. We demonstrate theoretically and experimentally the existence of two different superconducting states appearing when the wire is driven out of equilibrium by an applied bias, called the global and bimodal superconducting states. The different states are identified by using two-probe measurements of the wire, and measurements of the local density of states with tunneling probes. The analysis is performed within the framework of the quasiclassical kinetic equations for diffusive superconductors.
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Zhang, W., Miao, W., Yao, Q. J., Lin, Z. H., Shi, S. C., Gao, J. R., et al. (2012). Spectral response and noise temperature of a 2.5 THz spiral antenna coupled NbN HEB mixer. Phys. Procedia, 36, 334–337.
Abstract: We report on a 2.5 THz spiral antenna coupled NbN hot electron bolometer (HEB) mixers, fabricated with in-situ process. The receiver noise temperature with lowest value of 1180 K is in good agreement with calculated quantum efficiency factor as a function of bias voltage. In addition, the measured spectral response of the spiral antenna coupled NbN HEB mixer shows broad frequency coverage of 0.8-3 THz, and corrected response for optical losses, FTS, and coupling efficiency between antenna and bolometer falls with frequency due to diffraction-limited beam of lens/antenna combination.
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Tuchak, A. N., Gol’tsman, G. N., Kitaeva, G. K., Penin, A. N., Seliverstov, S. V., Finkel, M. I., et al. (2012). Generation of nanosecond terahertz pulses by the optical rectification method. JETP Lett., 96(2), 94–97.
Abstract: The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2.
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Pentin, I. V., Smirnov, A. V., Ryabchun, S. A., Ozhegov, R. V., Gol’tsman, G. N., Vaks, V. L., et al. (2012). Semiconducting superlattice as a solid-state terahertz local oscillator for NbN hot-electron bolometer mixers. Tech. Phys., 57(7), 971–974.
Abstract: We present the results of our studies of the semiconducting superlattice (SSL) frequency multiplier and its application as part of the solid state local oscillator (LO) in the terahertz heterodyne receiver based on a NbN hot-electron bolometer (HEB) mixer. We show that the SSL output power level increases as the ambient temperature is lowered to 4.2 K, the standard HEB operation temperature.
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