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Sych D, Shcherbatenko M, Elezov M, Goltsman GN. Towards the improvement of the heterodyne receiver sensitivity beyond the quantum noise limit. In: Proc. 29th Int. Symp. Space Terahertz Technol.; 2018. p. 245–7.
Abstract: Noise reduction in heterodyne receivers of the terahertz range is an important issue for astronomical applications. Quantum fluctuations, also known as shot noise, prohibit errorless measurements of the amplitude of electro-magnetic waves, and introduce the so-called standard quantum limit (SQL) on the minimum error of the heterodyne measurements. Nowadays, the sensitivity of modern heterodyne receivers approaches the SQL, and the growing demand for the improvement of measurement precision stimulates a number of both theoretical and experimental efforts to design novel measurement techniques aimed at overcoming the SQL. Here we demonstrate the first steps towards the practical implementation of a sub-SQL quantum receiver. As the principal resources, it requires a highly efficient single-photon counting detector and an interferometer-based scheme for mixing the signal with a low-power local oscillator. We describe the idea of such receiver and its main components.
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Korneeva Y, Vodolazov D, Florya I, Manova N, Smirnov E, Korneev A, et al. Single photon detection in micron scale NbN and α-MoSi superconducting strips. In: EPJ Web Conf. Vol 190.; 2018. 04010 (1 to 2).
Abstract: We experimentally demonstrate the single photon detection in straight micrometer-wide NbN and α-MoSi bridges. Width of the bridges is 2 µm, while the wavelength of the photon changes from 408 to 1550 nm and critical current exceeds 50% of the depairing current. Obtained results offer the alternative route for design of detectors without resonator and meander structure and indirectly confirm vortex assisted mechanism of single photon detection.
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Goltsman G, Naumov AV, Gladush MG, Karimullin KR. Quantum photonic integrated circuits with waveguide integrated superconducting nanowire single-photon detectors. In: EPJ Web Conf. Vol 190.; 2018. 02004 (1 to 2).
Abstract: We show the design, a history of development as well as the most successful and promising approaches for QPICs realization based on hybrid nanophotonic-superconducting devices, where one of the key elements of such a circuit is a waveguide integrated superconducting single-photon detector (WSSPD). The potential of integration with fluorescent molecules is discussed also.
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Goltsman G. Superconducting thin film as infrared heterodyne and direct detectors. In: 16th ISEC.; 2017. p. 1–3.
Abstract: We present our recent achievements in the development of superconducting nanowire single-photon detectors (SNSPDs) integrated with optical waveguides on a chip. We demonstrate both single-photon counting with up to 90% on-chip-quantum-efficiency (OCDE), and the heterodyne mixing with a close to the quantum limit sensitivity at the telecommunication wavelength using single device.
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Korneeva Y, Florya I, Vdovichev S, Moshkova M, Simonov N, Kaurova N, et al. Comparison of hot spot formation in nbn and mon thin superconducting films after photon absorption. IEEE Trans Appl Supercond. 2017;27(4):1–4.
Abstract: In superconducting single-photon detectors (SSPD), the efficiency of local suppression of superconductivity and hotspot formation is controlled by diffusivity and electron-phonon interaction time. Here, we selected a material, 3.6-nm-thick MoNx film, which features diffusivity close to those of NbN traditionally used for SSPD fabrication, but with electron-phonon interaction time an order of magnitude larger. In MoN ∞ detectors, we study the dependence of detection efficiency on bias current, photon energy, and strip width, and compare it with NbN SSPD. We observe nonlinear current-energy dependence in MoNx SSPD and more pronounced plateaus in dependences of detection efficiency on bias current, which we attribute to longer electron-phonon interaction time.
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