|
|
Varyukhin, S. V., Zakharov, A. A., Gershenzon, E. M., Gol'tsman, G. N., Ptitsyna, N. G., & Chulkova, G. M. (1990). AC losses and submillimeter absorption in single crystals La2CuO4. Phys. B Condens. Mat., 165-166, 1269–1270.
Abstract: The La2CuO4 single crystals were used to carry out the measurements of transmission spectra within the submillimeter range of wavelengths, as well as the capacitance C and conductivity G in the region of acoustic frequencies of the metal-dielectric-La2Cu04 system at low temperatures. The optical spectra display a threshold character. There takes place a sharp decreasing of transmission signal in the energy range of hυ>1.5meV. The C(ω,T) and G(ω,T) dependences have a universal form characteristic of relaxation processes of the Debye type. The relaxation time dependence displays a thermoactivation character τ(T)-exp(ξ/T) with a gap value of ξ≃2meV,coinciding with the optical one. It is assumed that there exist excitations with a characteristic energy ~ 2meV in La2Cu04.A possible nature of the revealed low-energy excitations is discussed.
|
|
|
|
Gershenzon, E. M., Gol’tsman, G. N., Sergeev, A., & Semenov, A. D. (1990). Picosecond response of YBaCuO films to electromagnetic radiation. In W. Gorzkowski, M. Gutowski, A. Reich, & H. Szymczak (Eds.), Proc. European Conf. High-Tc Thin Films and Single Crystals (pp. 457–462).
Abstract: Radiation-induced change of the resistance was studied in the resistive state of YBaCuO films. Electron-phonon relaxation time T h was determmed from direct ep measurements and analysis of quasistationary electron heating. Temperature dependence of That TS 40 K was found to – ep be T h.. T'. The resul ts show that ep detectors with the response time of few picosecond at nitrogen temperature can be realized.
|
|
|
|
Gershenzon, E. M., Goltsman, G. N., & Orlov, L. (1976). Investigation of population and ionization of donor excited states in Ge. In Physics of Semiconductors (pp. 631–634). North-Holland Publishing Co.
|
|
|
|
Matyushkin, Y., Fedorov, G., Moskotin, M., Danilov, S., Ganichev, S., & Goltsman, G. (2020). Gate-mediated helicity sensitive detectors of terahertz radiation with graphene-based field effect transistors. In Graphene and 2dm Virt. Conf..
Abstract: Closing of the so-called terahertz gap results in an increased demand for optoelectronic devices operating in the frequency range from 0.1 to 10 THz. Active plasmonic in field effect devices based on high-mobility two-dimensional electron gas (2DEG) opens up opportunities for creation of on-chip spectrum [1] and polarization [2] analysers. Here we show that single layer graphene (SLG) grown using CVD method can be used for an all-electric helicity sensitive polarization broad analyser of THz radiation. Allourresults show plasmonic nature of response. Devices are made in a configuration ofa field-effect transistor (FET) with a graphene channel that has a length of 2 mkm and a width of 5.5 mkm. Response of opposite polarity to clockwise and anticlockwise polarized radiation is due to special antenna design (see Fig.1c) as follow works [2,3]. Our approaches can be extrapolated to other 2D materials and used as a tool to characterize plasmonic excitations in them. [1]Bandurin, D. A., etal.,Nature Communications, 9(1),(2018),1-8.[2]Drexler, C.,etal.,Journal of Applied Physics, 111(12),(2012),124504.[3]Gorbenko, I. V.,et al.,physica status solidi (RRL)–Rapid Research Letters, 13(3),(2019),1800464.
|
|
|
|
Baselmans, J. J. A., Hajenius, M., Gao, J., de Korte, P., Klapwijk, T. M., Voronov, B., et al. (2004). Doubling of sensitivity and bandwidth in phonon-cooled hot-electron bolometer mixers. In J. Zmuidzinas, W. S. Holland, & S. Withington (Eds.), Proc. SPIE (Vol. 5498, pp. 168–176). SPIE.
Abstract: NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between the NbN bolometer and the contact pad. We compare identical bolometers, with different NbN – contact pad interfaces, coupled with a spiral antenna. We find that cleaning the NbN interface and adding a thin additional superconductor prior to the gold contact deposition improves the noise temperature and the bandwidth of the HEB mixers with more than a factor of 2. We obtain a DSB noise temperature of 950 K at 2.5 THz and a Gain bandwidth of 5-6 GHz. For use in real receiver systems we design small volume (0.15x1 micron) HEB mixers with a twin slot antenna. We find that these mixers combine good sensitivity (900 K at 1.6 THz) with low LO power requirement, which is 160 – 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5.
|
|
|
|
Goltsman, G. (2017). Superconducting thin film nanostructures as terahertz and infrared heterodyne and direct detectors. In 16th ISEC (Th-I-QTE-03 (1 to 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-chipquantum-efficiency (OCDE), and the heterodyne mixing with a close to the quantum limit sensitivity at the telecommunication wavelength using single device.
|
|
|
|
Gol’tsman, G. N. (2014). Overview of recent results for superconducting NbN terahertz and optical detectors and mixers.
Abstract: We present our recent achievements in the development of sensitive and ultrafast thin-film superconducting sensors: hot-electron bolometers (HEB), HEB-mixers for terahertz range and infrared single-photon counters. These sensors have already demonstrated a performance that makes them devices-of-choice for many terahertz and optical applications.
|
|
|
|
Averkin, A. S., Shishkin, A. G., Chichkov, V. I., Voronov, B. M., Goltsman, G. N., Karpov, A., et al. (2014). Tunable frequency-selective surface based on superconducting split-ring resonators. In 8th Metamaterials.
Abstract: We study a possibility to use the 2D superconducting metamaterial as a tunable frequency-selective surface (FSS). The proposed FSS is made of sub-wavelength size (l/14) metamaterial unit cells, where a split-ring resonator is embedded in a small iris aperture in a metal plane. The split-ring resonator is made of NbN film, and its resonance frequency is tuned by the temperature of the sample, changing the kinetic inductance of NbN film. The Ansoft HFSS simulation predicts the FSS tuning range of about 10-20 %. The developed superconducting FSS may be used as a tunable band-pass filter or modulator.
|
|
|
|
Zhang, J., Verevkin, A., Slysz, W., Chulkova, G., Korneev, A., Lipatov, A., et al. (2017). Time-resolved characterization of NbN superconducting single-photon optical detectors. In J. C. Armitage (Ed.), Proc. SPIE (Vol. 10313, 103130F (1 to 3)). SPIE.
Abstract: NbN superconducting single-photon detectors (SSPDs) are very promising devices for their picosecond response time, high intrinsic quantum efficiency, and high signal-to-noise ratio within the radiation wavelength from ultraviolet to near infrared (0.4 gm to 3 gm) [1-3]. The single photon counting property of NbN SSPDs have been investigated thoroughly and a model of hotspot formation has been introduced to explain the physics of the photon- counting mechanism [4-6]. At high incident flux density (many-photon pulses), there are, of course, a large number of hotspots simultaneously formed in the superconducting stripe. If these hotspots overlap with each other across the width w of the stripe, a resistive barrier is formed instantly and a voltage signal can be generated. We assume here that the stripe thickness d is less than the electron diffusion length, so the hotspot region can be considered uniform. On the other hand, when the photon flux is so low that on average only one hotspot is formed across w at a given time, the formation of the resistive barrier will be realized only when the supercurrent at sidewalks surpasses the critical current (jr) of the superconducting stripe [1]. In the latter situation, the formation of the resistive barrier is associated with the phase-slip center (PSC) development. The effect of PSCs on the suppression of superconductivity in nanowires has been discussed very recently [8, 9] and is the subject of great interest.
|
|
|
|
Verevkin, A., Zhang, J., Pearlman, A., Slysz, W., Sobolewski, R., Korneev, A., et al. (2004). Ultimate sensitivity of superconducting single-photon detectors in the visible to infrared range.
Abstract: We present our quantum efficiency (QE) and noise equivalent power (NEP) measurements of the meandertype ultrathin NbN superconducting single-photon detector in the visible to infrared radiation range. The nanostructured devices with 3.5-nm film thickness demonstrate QE up to~ 10% at 1.3–1.55 µm wavelength, and up to 20% in the entire visible range. The detectors are sensitive to infrared radiation with the wavelengths down to~ 10 µm. NEP of about 2× 10-18 W/Hz1/2 was obtained at 1.3 µm wavelength. Such high sensitivity together with GHz-range counting speed, make NbN photon counters very promising for efficient, ultrafast quantum communications and another applications. We discuss the origin of dark counts in our devices and their ultimate sensitivity in terms of the resistive fluctuations in our superconducting nanostructured devices.
|
|
