Tretyakov, I., Kaurova, N., Voronov, B. M., & Goltsman, G. N. (2018). About effect of the temperature operating conditions on the noise temperature and noise bandwidth of the terahertz range NbN hot-electron bolometers. In Proc. 29th Int. Symp. Space Terahertz Technol. (113).
Abstract: Results of an experimental study of the noise temperature (Tn) and noise bandwidth (NBW) of the superconductor NbN hot-electron bolometer (HEB) mixer as a function of its temperature (Tb) and NbN bridge length are presented. It was determined that the NBW of the mixer is significantly wider at temperatures close to the critical ones (Tc) than are values measured at 4.2 K. The NBW of the mixer measured at the heterodyne frequency of 2.5 THz at temperature Tb close to Tc was ~13 GHz, as compared with 6 GHz at Tb = 4.2 K. This experiment clearly demonstrates the limitation of the thermal flow from the NbN bridge at Tb ≪ Tc for mixers manufactured by the in situ technique. This limitation is close in its nature to the Andreev reflection on the superconductor/metal boundary. In this case, the noise temperature of the studied mixer increased from 1100 to 3800 K.
|
Rath, P., Vetter, A., Kovalyuk, V., Ferrari, S., Kahl, O., Nebel, C., et al. (2016). Travelling-wave single-photon detectors integrated with diamond photonic circuits: operation at visible and telecom wavelengths with a timing jitter down to 23 ps. In J. - E. Broquin, & G. N. Conti (Eds.), Integrated Optics: Devices, Mat. Technol. XX (Vol. 9750, pp. 135–142). Spie.
Abstract: We report on the design, fabrication and measurement of travelling-wave superconducting nanowire single-photon detectors (SNSPDs) integrated with polycrystalline diamond photonic circuits. We analyze their performance both in the near-infrared wavelength regime around 1600 nm and at 765 nm. Near-IR detection is important for compatibility with the telecommunication infrastructure, while operation in the visible wavelength range is relevant for compatibility with the emission line of silicon vacancy centers in diamond which can be used as efficient single-photon sources. Our detectors feature high critical currents (up to 31 μA) and high performance in terms of efficiency (up to 74% at 765 nm), noise-equivalent power (down to 4.4×10-19 W/Hz1/2 at 765 nm) and timing jitter (down to 23 ps).
|
Iomdina, E. N., Seliverstov, S. V., Sianosyan, A. A., Teplyakova, K. O., Rusova, A. A., & Goltsman, G. N. (2018). Terahertz scanning for evaluation of corneal and scleral hydration. STM, 10(4), 143–149.
Abstract: The aim of the investigation was to study the prospects of using continuous THz scanning of the cornea and the sclera to determine water concentration in these tissues and on the basis of the obtained data to develop the experimental installation for monitoring corneal and scleral hydration degree.Materials and Methods. To evaluate corneal and scleral transmittance and reflectance spectra in the THz range, the developed experimental installations were used to study 3 rabbit corneas and 3 scleras, 2 whole rabbit eyes, and 3 human scleras. Besides, two rabbit eyes were studied in vivo prior to keratorefractive surgery as well as 10 and 21 days following the surgery (LASIK).Results. There have been created novel experimental installations enabling in vitro evaluation of frequency dependence of corneal and scleral transmittance coefficients and reflectance coefficients on water percentage in the THz range. Decrease in corneal water content by 1% was found to lead to reliably established decrease in the reflected signal by 13%. The reflectance spectrum of the whole rabbit eye was measured in the range of 0.13–0.32 THz. The study revealed the differences between the indices of rabbit cornea and sclera, as well as rabbit and human sclera. There was developed a laboratory model of the installation for in vivo evaluation of corneal and scleral hydration using THz radiation.Conclusion. The preliminary findings show that the proposed technique based on the use of continuous THz radiation can be employed to create a device for noninvasive control of corneal and scleral hydration.
|
Glejm, A. V., Anisimov, A. A., Asnis, L. N., Vakhtomin, Y. B., Divochiy, A. V., Egorov, V. I., et al. (2014). Quantum key distribution in an optical fiber at distances of up to 200 km and a bit rate of 180 bit/s. Bulletin of the Russian Academy of Sciences. Physics, 78(3), 171–175.
Abstract: An experimental demonstration of a subcarrier-wave quantum cryptography system with superconducting single-photon detectors (SSPDs) that distributes a secure key in a single-mode fiber at distance of 25 km with a bit rate of 800 kbit/s, a distance of 100 km with a bit rate of 19 kbit/s, and a distance of 200 km with a bit rate of 0.18 kbit/s is described.
|
|
Goltsman, G. N. (2006). Submillimeter superconducting receivers for astronomy, atmospheric studies and other applications. In 31nd IRMW / 14th ICTE (177).
|
