Frequency tunability and mode switching of 2.5 THz quantum cascade lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Richter, Heiko, Semenov, Alexey, Tredicucci, Alessandro, Mahler, Lukas, ...
Spectral characteristics of quantum cascade lasers operating at about 2.5 terahertz have been investigated by means of high-resolution mixing spectroscopy. Linewidth, frequency tunability and...
Improved energy resolution of a superconducting single-photon detector (2008)
Semenov, Alexey, Haas, Philipp, Hübers, Heinz-Wilhelm, Ilin, Konstantin, Siegel, Michael, Kirste, Alexander, ...
We demonstrated successful operation of an NbN single photon detector in the temperature range from 6 K to 1.2 K using a 3He sorption refrigerator combined with a pulse-tube mechanical cooler. The...
Frequency tunability and mode switching of quantum cascade lasers operating at 2.5 THz (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Richter, Heiko, Semenov, Alexey, Tredicucci, Alessandro, Green, Richard, ...
Quantum cascade lasers (QCLs) are promising devices for local oscillators in terahertz heterodyne receivers. The lasing mechanism is based on intersubband transitions in the conduction band of...
Current-induced critical state in NbN thin-film structures (2008)
Ilin, Konstantin, Siegel, Michael, Engel, Andreas, Bartolf, Holger, Schilling, Andreas, Semenov, Alexey, ...
The temperature dependence of the critical current of NbN thin-film bridges was experimentally studied. At low temperatures we observed significant enhancement (up to two times at 4 K) of the...
Imaging terahertz radar for security applications (2008)
Semenov, Alexey, Richter, Heiko, Böttger, Ute, Hübers, Heinz-Wilhelm
Detection of concealed threats is a key issue in public security. In short range applications, passive imagers operating at millimeter wavelengths fulfill this task. However, for larger distances,...
Energy resolution of a superconducting nanowire single-photon detector (2008)
Semenov, Alexey, Haas, Philipp, Günther, Burdhardt, Hübers, Heinz-Wilhelm, Ilin, Konstantin, Siegel, Michael
An energy resolution of 0.6 eV was achieved with an NbN superconducting nanowire single-photon detector for near infrared photons in the energy range from 1.2 eV to 0.8 eV. The detector operates at 6...
Vortex-based single-photon response in nanostructured superconducting detectors (2008)
Semenov, Alexey, Haas, Philipp, Hübers, Heinz-Wilhelm, Ilin, Konstantin, Siegel, Michael, Kirste, Alexander, ...
In nanostructured superconducting films interaction of magnetic vortices with radiation quanta provides an additional mechanism of radiation detection. Below the Kosterlitz–Thouless topological...
Distant detection of hidden objects with a THz imaging radar (2007)
Semenov, Alexey, Richter, Heiko, Böttger, Ute, Smirnov, Andrey, Hübers, Heinz-Wilhelm
Detection of concealed threats at large distances is a key issue in public security. The paper describes a 0.8-THz radar that is capable to indicate hidden objects at a distance of more than 20 meter...
An energy-resolving superconducting nanowire photon counter (2007)
Semenov, Alexey, Haas, Philipp, Günther, Burghardt, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael, ...
We report on the energy-resolving capability of a superconducting NbN nanowire photon counter, which is read out by a superconducting quantum interference device. For counters operated at 6.5 K, a...
Imaging THz radar for security applications (2007)
Semenov, Alexey, Richter, Heiko, Böttger, Ute, Hübers, Heinz-Wilhelm, Smirnov, Andrey
Detection of concealed threats is a key issue in public security. In short range applications, passive imagers operating at millimetre wavelengths fulfill this task. However, for larger distances,...
Energy resolution and sensitivity of a superconducting quantum detector (2007)
Semenov, Alexey, Haas, Philipp, Il'in, Konstantin, Hübers, Heinz-Wilhelm, Siegel, Michael, Engel, Andreas, ...
Single-photon detectors from thin niobium nitride nanostrips show moderate energy resolution along with the cut-off of the quantum efficiency in the near-infrared spectral range. To describe the...
Energy resolution and sensitivity of a superconducting quantum detector (2007)
Semenov, Alexey, Haas, Philipp, Ilin, Konstantin, Hübers, Heinz-Wilhelm, Siegel, Michael, Engel, Andreas, ...
Single-photon detectors from thin niobium nitride nanostrips show moderate energy resolution along with the cut-off of the quantum efficiency in the near-infrared spectral range. To describe the...
Terahertz performance of integrated lens antennas with a hot-electron bolometer (2007)
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-Wilhelm, Günther, Burghardt, Smirnov, Andrey, Ilin, Konstantin, ...
Radiation coupling efficiency and directive properties of integrated lens antennas with log-spiral, log-periodic and double-slot planar feeds coupled to a hot-electron bolometer were experimentally...
GREAT: the German first light heterodyne instrument for SOFIA (2007)
Graf, Urs U., Heyminck, Stefan, Güsten, Rolf, Hartogh, Paul, Hübers, Heinz-Wilhelm, Stutzki, Jürgen, ...
Engel, Andreas, Semenov, Alexey, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael
Superconducting thin films and micro- and nanostructured superconducting elements have enormous potential for applications in electronics and as highly sensitive detectors. We present recent studies...
Semenov, Alexey, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael
Auf dem elektronischen Nichtgleichgewicht basierende Detektoren sind wegen ihrer hohen Empfindlichkeit und Schnelligkeit bereits wichtiger Bestandteil vieler Anwendungen in Astronomie und...
Superconducting-normal metal bi-layers for antenna structures of hot-elektron detector (2006)
Stockhausen, Axel, Neuhaus, Manfred, Stassen, Alexander, Il'in, Konstantin, Siegel, Michael, Semenov, Alexey, ...
We have developed a quasi-optical version of a superconducting hot-electron detector (HED) suitable for application in the THz frequency range based on a sub-micron bridge made from ultra-thin...
NbN ultra-thin film Hot-Electron Detector for THZ application: Fabrication issues (2006)
Il'in, Konstantin, Stockhausen, Axel, Neuhaus, Manfred, Wermund, Hans-Jürgen, Siegel, Michael, Semenov, Alexey, ...
Superconducting Hot-Electron Detector (HED) is one of promising devices for a wide range of THz applications: astronomy, spectroscopy, imaging, and security. Actually HED is a rectangular strip of...
Evidence of non-bolometric mixing in the bandwidth of a hot-electron bolometer (2006)
Semenov, Alexey, Il'in, Konstantin, Siegel, Michael, Smirnov, Andrey, Pavlov, Sergey, Richter, Heiko, ...
The gain bandwidth of a superconducting NbN hot-electron mixer was measured at local oscillator (LO) frequencies 2.5 THz, 0.6 THz and 0.3 THz and compared to presently known bolometric mixer models....
Fluctuation effects in superconducting nanostrips (2006)
Engel, Andreas, Semenov, Alexey, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael
Superconducting fluctuations in long and narrow strips made from ultrathin NbN films, have been investigated. For large bias currents close to the critical current fluctuations led to localized,...
Terahertz performance of quasioptical front-ends with a hot-electron bolometer (2006)
Semenov, Alexey, Richter, Heiko, Günther, Burghardt, Hübers, Heinz-Wilhelm, Karamarkovic, Jugoslav
We present terahertz performance of quasioptical front-ends consisting of a hotelectron bolometer imbedded in a planar feed antenna and integrated with an immersion lens. The impedance and radiation...
Integrated Planar Antennas at Terahertz Waves (2006)
Semenov, Alexey, Richter, Heiko, Günther, Burghardt, Hübers, Heinz-Wilhelm, Karamarkovich, Jugoslav
We present the terahertz performance of integrated lens antennas consisting of a double-slot or a log-spiral planar feed and a synthesized elliptical lens. The radiation pattern and the impedance of...
Noise Bolometer for Terahertz Waves (2006)
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael
An advantage of superconducting detectors is a much lower noise in comparison to their semiconductor counterparts. We have studied the magnitude and spectrum of electric noise in thin superconducting...
Passive Terahertz Wave Imaging with a Single Bolometer and with a Bolometer Array (2006)
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-WIlhelm, Zakosarenko, Vjatcheslav, May, Torsten, Anders, Susanne, ...
Detection of concealed threats like guns, knifes or explosives is of prime importance at airports and other public places. Passive millimetre wave (mmW) imagers operating at frequencies up to almost...
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-Wilhelm, Zakosarenko, Vjatcheslav, May, Torsten, Anders, Susanne, ...
Detection of concealed threats is of prime importance for public security. In short range applications, passive imagers operating at millimeter wavelengths have been demonstrated to fulfill this...
Semenov, Alexey, Engel, Andreas, Hübers, Heinz-Wilhelm, Il´in, Konstantin, Siegel, Michael
We have studied supercurrent-assisted formation of the resistive state in nano-structured disordered superconducting Nb(N) films after absorption of a single optical to near-infrared photon. The...
Superconducting noise bolometer for terahertz radiation (2005)
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael
We present a superconducting noise bolometer that is a bolometric detector sensing radiation via radiation-induced changes of its own microwave noise. The detector represents a nano-strip made from a...
Noise of a superconducting photon detector (2005)
Semenov, Alexey, Engel, Andreas, Hübers, Heinz-Wilhelm, Il´in, Konstantin, Siegel, Michael
We have studied electrical noise of photon detectors representing long and narrow superconducting strips. For large bias currents close to the critical current fluctuations lead to localized,...
Ultra-thin NBN and TiN films for radiation sensors (2005)
Il´in, Konstantin, Siegel, Michael, Semenov, Alexey, Hübers, Heinz-Wilhelm, Hollmann, Evgeny
Ultra-thin superconducting films are widely used for fabrication of modern radiation sensors. The advantages of the superconductor based devices are a low noise level, an outstanding sensitivity and...
Terahertz performance of integrated double-slot antennas (2005)
Semenov, Alexey, Richter, Heiko, Günther, Burghardt, Hübers, Heinz-Wilhelm, Karamarkovic, Jugoslav
We present the terahertz performance of integrated lens antennas consisting of a double-slot planar feed antenna and a synthesized elliptical lens. The radiation pattern and the impedance of the...
Integrated planar log-spiral antenna at terahertz waves (2005)
Semenov, Alexey, Richter, Heiko, Günther, Burghardt, Hübers, Heinz-Wilhelm, Karamarcovic, Jugoslav
We present terahertz performance of integrated lens antennas consisting of a complementary log-spiral planar feed and a synthesized elliptical lens. The radiation pattern and the impedance of the...
Current-noise superconducting bolometer for terahertz waves (2005)
Semenov, Alexey, Richter, Heiko, Hübers, Heinz-Wilhelm, Il´in, Konstantin, Siegel, Michael, Engel, Andreas
An advantage of superconducting detectors is a much lower noise in comparison to their semiconductor counterparts. We have studied the magnitude and spectrum of electric noise in thin superconducting...
Terahertz-Heterodynempfänger mit Quantenkaskadenlaser und supraleitendem Mischer (2005)
Semenov, Alexey, Richter, Heiko, Pavlov, Sergey, Hübers, Heinz-Wilhelm, Il´in, Konstantin, Siegel, Michael, ...
Die hochauflösende Spektroskopie atomarer und molekularer Emissions- und Absorptionslinien im Terahertz (THz)-Spektralbereich liefert Informationen über den stellaren-interstellaren Lebenszyklus...
Spectral performance of a single-photon detector (2005)
Semenov, Alexey, Engel, Andreas, Hübers, Heinz-WIlhelm, Il´in, Konstantin, Siegel, Michael
We have experimentally studied the supercurrent-assisted formation of the resistive state in nano-structured disordered superconducting Nb(N) films after absorption of a single optical to...
Terahertz performance of quasioptical front-ends with a hot-electron bolometer (2005)
Semenov, Alexey, Richter, Heiko, Günther, Burghardt, Hübers, Heinz-Wilhelm, Karamarkovic, Jugoslav
We present terahertz performance of quasioptical front-ends consisting of a hot-electron bolometer imbedded in a planar feed antenna and integrated with an immersion lens. The impedance and radiation...