Pyatkov, F., Khasminskaya, S., Kovalyuk, V., Hennrich, F., Kappes, M. M., Goltsman, G. N., et al. (2017). Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers. Beilstein J. Nanotechnol., 8, 38–44.
Abstract: Carbon nanotubes (CNTs) have recently been integrated into optical waveguides and operated as electrically-driven light emitters under constant electrical bias. Such devices are of interest for the conversion of fast electrical signals into optical ones within a nanophotonic circuit. Here, we demonstrate that waveguide-integrated single-walled CNTs are promising high-speed transducers for light-pulse generation in the gigahertz range. Using a scalable fabrication approach we realize hybrid CNT-based nanophotonic devices, which generate optical pulse trains in the range from 200 kHz to 2 GHz with decay times below 80 ps. Our results illustrate the potential of CNTs for hybrid optoelectronic systems and nanoscale on-chip light sources.
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Zorin, M., Lindgren, M., Danerud, M., Karasik, B., Winkler, D., Gol'tsman, G., et al. (1995). Nonequilibrium and bolometric responses of YBaCuO thin films to high-frequency modulated laser radiation. J. Supercond., 8(1), 11–15.
Abstract: Picosecond nonequilibrium and slow bolometric responses to infrared radiation from a patterned high-T c superconducting (HTS) film in resistive and normal states deposited onto LaAlO3, NdGaO3, and MgO substrates were investigated using both pulse and modulation techniques. The response time of 35 ps to a laser pulse of 17 ps FWHM has been observed. The intrinsic response time of the fast process is expected to be about a few picoseconds. The modulation technique, being free from the disadvantages of pulse methods (poor sensitivity, limited dynamic range), makes the detailed study of a number of relaxation processes possible. Besides the nonequilibrium response, two kinds of bolometric processes, namely phonon transport through the film-substrate interface and phonon thermal diffusion in a substrate, manifest themselves in certain frequency dependences.
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Kawamura, J. H., Tong, C. - Y. E., Blundell, R., Cosmo Papa, D., Hunter, T. R., Gol'tsman, G., et al. (1999). An 800 GHz NbN phonon-cooled hot-electron bolometer mixer receiver. IEEE Trans. Appl. Supercond., 9(2), 3753–3756.
Abstract: We describe a heterodyne receiver developed for astronomical applications to operate in the 350 /spl mu/m atmospheric window. The waveguide receiver employs a superconductive NbN phonon-cooled hot-electron bolometer mixer. The double sideband receiver noise temperature closely follows 1 kGHz/sup -1/ across 780-870 GHz, with the intermediate frequency centered at 1.4 GHz. The conversion loss is about 15 dB. The receiver was installed for operation at the University of Arizona/Max Planck Institute for Radio Astronomy Submillimeter Telescope facility. The instrument was successfully used to conduct test observations of a number of celestial sources in a number of astronomically important spectral lines.
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Schwaab, G. W., Sirmain, G., Schubert, J., Hubers, H. - W., Gol'tsman, G., Cherednichenko, S., et al. (1999). Investigation of NbN phonon-cooled HEB mixers at 2.5 THz. IEEE Trans. Appl. Supercond., 9(2), 4233–4236.
Abstract: The development of superconducting hot electron bolometric (HEB) mixers has been a big step forward in the direction of quantum noise limited mixer performance at THz frequencies. Such mixers are crucial for the upcoming generation of airborne and spaceborne THz heterodyne receivers. In this paper we report on new results on a phonon-cooled NbN HEB mixer using e-beam lithography. The superconducting film is 3 nm thick. The mixer is 0.2 μm long and 1.5 μm wide and it is integrated in a spiral antenna on a Si substrate. The device is quasi-optically coupled through a Si lens and a dielectric beam combiner to the radiation of an optically pumped FIR ring gas laser cavity. The performance of the mixer at different THz frequencies from 0.69 to 2.55 THz with an emphasis on 2.52 THz is demonstrated. At 2.52 THz minimum DSB noise temperatures of 4200 K have been achieved at an IF of 1.5 GHz and a bandwidth of 40 MHz with the mixer mounted in a cryostat and a 0.8 m long signal path in air.
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Sidorova, M. V., Divochiy, A. V., Vakhtomin, Y. B., & Smirnov, K. V. (2015). Ultrafast superconducting single-photon detector with a reduced active area coupled to a tapered lensed single-mode fiber. J. Nanophoton., 9(1), 093051.
Abstract: This paper presents an ultrafast niobium nitride (NbN) superconducting single-photon detector (SSPD) with an active area of 3×3 μm2 that offers better timing performance metrics than the previous SSPD with an active area of 7×7 μm2. The improved SSPD demonstrates a record timing jitter (<25 ps), an ultrashort recovery time (<2 ns), an extremely low dark count rate, and a high detection efficiency in a wide spectral range from visible part to near infrared. The record parameters were obtained due to the development of a new technique providing effective optical coupling between a detector with a reduced active area and a standard single-mode telecommunication fiber. The advantages of the new approach are experimentally confirmed by taking electro-optical measurements.
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