Lusche, R., Semenov, A., Ilin, K., Siegel, M., Korneeva, Y., Trifonov, A., et al. (2014). Effect of the wire width on the intrinsic detection efficiency of superconducting-nanowire single-photon detectors. J. Appl. Phys., 116(4), 043906 (1 to 9).
Abstract: A thorough spectral study of the intrinsic single-photon detection efficiency in superconducting TaN and NbN nanowires with different widths has been performed. The experiment shows that the cut-off of the intrinsic detection efficiency at near-infrared wavelengths is most likely controlled by the local suppression of the barrier for vortex nucleation around the absorption site. Beyond the cut-off quasi-particle diffusion in combination with spontaneous, thermally activated vortex crossing explains the detection process. For both materials, the reciprocal cut-off wavelength scales linearly with the wire width where the scaling factor agrees with the hot-spot detection model.
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Ferrari, S., Kovalyuk, V., Vetter, A., Lee, C., Rockstuhl, C., Semenov, A., et al. (2019). Analysis of the detection response of waveguide-integrated superconducting nanowire single-photon detectors at high count rate. Appl. Phys. Lett., 115(10), 101104.
Abstract: Nanophotonic circuitry and superconducting nanowires have been successfully combined for detecting single photons, propagating in an integrated photonic circuit, with high efficiency and low noise and timing uncertainty. Waveguide-integrated superconducting nanowire single-photon detectors (SNSPDs) can nowadays be engineered to achieve subnanosecond recovery times and can potentially be adopted for applications requiring Gcps count rates. However, particular attention shall be paid to such an extreme count rate regime since artifacts in the detector functionality emerge. In particular, a count-rate dependent detection efficiency has been encountered that can compromise the accuracy of quantum detector tomography experiments. Here, we investigate the response of waveguide-integrated SNSPDs at high photon flux and identify the presence of parasitic currents due to the accumulation of charge in the readout electronics to cause the above-mentioned artifact in the detection efficiency. Our approach allows us to determine the maximum photon count rate at which the detector can be operated without adverse effects. Our findings are particularly important to avoid artifacts when applying SNSPDs for quantum tomography.
We acknowledge support through ERC Consolidator Grant No. 724707 and from the Deutsche Forschungsgemeinschaft through Project No. PE 1832/5-1,2, as well as funding by the Volkswagen Foundation. This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant Agreement No. 675745. V.K. and G.G. acknowledge support from the Russian Science Foundation Project No. 16-12-00045 (NbN film deposition and testing). A.V. acknowledges support from the Karlsruhe School of Optics and Photonics (KSOP).
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Jukna, A., Kitaygorsky, J., Pan, D., Cross, A., Perlman, A., Komissarov, I., et al. (2008). Dynamics of hotspot formation in nanostructured superconducting stripes excited with single photons. Acta Physica Polonica A, 113(3), 955–958.
Abstract: Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
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Bandurin, D. A., Gayduchenko, I., Cao, Y., Moskotin, M., Principi, A., Grigorieva, I. V., et al. (2018). Dual origin of room temperature sub-terahertz photoresponse in graphene field effect transistors. Appl. Phys. Lett., 112(14), 141101 (1 to 5).
Abstract: Graphene is considered as a promising platform for detectors of high-frequency radiation up to the terahertz (THz) range due to its superior electron mobility. Previously, it has been shown that graphene field effect transistors (FETs) exhibit room temperature broadband photoresponse to incoming THz radiation, thanks to the thermoelectric and/or plasma wave rectification. Both effects exhibit similar functional dependences on the gate voltage, and therefore, it was difficult to disentangle these contributions in previous studies. In this letter, we report on combined experimental and theoretical studies of sub-THz response in graphene field-effect transistors analyzed at different temperatures. This temperature-dependent study allowed us to reveal the role of the photo-thermoelectric effect, p-n junction rectification, and plasmonic rectification in the sub-THz photoresponse of graphene FETs.
D.A.B. acknowledges the Leverhulme Trust for financial support. The work of D.S. was supported by Grant No. 16-19-10557 of the Russian Scientific Foundation (theoretical model). G.F., I.G., M.M., and G.G. acknowledge the Russian Science Foundation [Grant No. 14-19-01308 (MIET, cryostat upgrade) and Grant No. 17-72-30036, (MSPU, photoresponse measurements), the Ministry of Education and Science of the Russian Federation (Contract No. 14.B25.31.0007 (device fabrication) and Task No. 3.7328.2017/LS (NEP analyses)] and the Russian Foundation for Basic Research [Grant No. 15-02-07841 (device design)]. The authors are grateful to Professor M. S. Shur for helpful discussions.
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Gol’tsman, G. N., Semenov, A. D., Sergeev, A. V., Aksaev, E. E., Gogidze, I. G., & Gershenzon, E. M. (1993). Electron-phonon interaction in thin YBaCuO films and fast detectors. In M. Meissner, & R. O. Pohl (Eds.), Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences (Vol. 112, pp. 184–185).
Abstract: The thin. YBaCuO film response to laser and submillimeter radiation demonstrates the picosecond nonequilibrium peak on the nanosecond bolometric background. Experimental data give an evidence for the spectral dependence of picosecond photoresponse probably due to a poor efficiency of electron multiplication processes. Presented results prove an availability of fast YBaCuO thin film detector.
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