Boron doped carbon nanotubes via ceramic catalysts (2009)
Bystrzejewski, Michal, Bachmatiuk, Alicja, Thomas, Jürgen, Ayala, Paola, Hübers, Heinz-Wilhelm, Gemming, Thomas, ...
A facile metal catalyst free route to synthesize boron doped (0.6%-1.0%)carbon nanotubes via ceramic nanowires in which the formation of the nanowires (probably serving as templates), the carbon...
Laser und Detektoren für THz-Anwendungen (2008)
Richter, Heiko, Böttger, Ute, Pavlov, Sergey, Semenov, Alexei, Hübers, Heinz-Wilhelm
Impact of the contact metallization on the performance of photoconductive THz antennas (2008)
Vieweg, N., Mikulics, M., Scheller, M., Ezdi, K., Hübers, Heinz-Wilhelm, Koch, M.
Both AuGe based alloys and Ti/Au metal layer stacks are widely used as ohmic metal contacts for photoconductive THz antennas made of low temperature grown GaAs. Here, we present the first systematic...
Richter, Heiko, Semenov, Alexei, Pavlov, Sergei, Mahler, Lukas, Tredicucci, Alessandro, Beere, Harvey E., ...
A liquid cryogen free terahertz (THz) heterodyne receiver in a pulse tube cooler has been realized. The receiver operates at 2.5 THz. It is based on a quantum cascade laser (QCL) as local oscillator...
Evidence of noncascade intracenter electron relaxation in shallow donor centers in silicon (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Haas, Philipp, Hovenier, Niels, Klaassen, Tjeerd, Zhukavin, Roman, ...
Noncascade relaxation of photoexcited electrons on ionized donor centers has been observed in silicon doped by arsenic (Si:As) at low temperatures. Emission spectra of the Si:As terahertz intracenter...
Richter, Heiko, Pavlov, Sergey, Semenov, Alexei, Hübers, Heinz-Wilhelm, Ill'in, Konstantin, Siegel, Michael, ...
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...
Hübers, Heinz-Wilhelm, Pavlov, Sergej, Richter, Heiko, Semenov, Alexei, Mahler, L., Tredicucci, A., ...
The terahertz (THz) portion of the elctromagnetic spectrum bears an amazing scientific potential in astronomy. High resolution spectroscopy in particular heterodyne spectroscopy of molecular...
Terahertz Applications and Radiometry (2008)
The terahertz spectral range is considered to be the least explored portion of the electromagnetic spectrum. In resent years several technological breakthroughs have paved the way for applying THz...
Towards Traceable Radiometry in the Terahertz Region (2008)
Werner, L., Hübers, Heinz-Wilhelm, Meindl, P., Müller, R., Richter, Heiko, Steiger, A.
PTB and DLR join their expertise and experience in optical radiometry and in THz techniques to perform what is to our knowledge the first traceable measurement of radiant power of a THz quantum...
Terahertz Raman laser based on silicon doped by phosphorus (2008)
Hübers, Heinz-Wilhelm, Pavlov, Sergei G., Böttger, Ute, Zhukavin, Roman Kh., Shastin, V.N., Hovenier, N., ...
Raman-type simulated emission at frequencies between 5.0 and 5.2 THz as well as between 6.1 and 6.4 THz has been realized in silicon crystals doped by phosphorus donors. The Stokes shift of 3.16 THz...
Towards Accurate Power Measurement in the Terahertz Region (2008)
Steiger, Andreas, Hübers, Heinz-Wilhelm, Meindl, P., Müller, R., Richter, Heiko, Werner, L.
To pave the way for comparable, accurate and reliable power measurements strongly missing throughout the THz community, PTB and DLR joined their expertise in optical radiometry and THz technology....
Surface roughness effects on the terahertz reflectance of pure explosive materials (2008)
Ortolani, M., Lee, J.S., Schade, U., Hübers, Heinz-Wilhelm
We studied the effect of surface roughness on terahertz reflectance spectra of explosives at both quasinormal and oblique incidence by Fourier-transform spectroscopy. The optical constants of...
Terahertz silicon lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Böttger, Ute, Zhukavin, Roman, Tsyplenkov, Veniamin, Kovalevsky, Konstantin, ...
Stimulated donor and Raman Stokes emission has been achieved under intracenter excitation and photoionization of shallow donor centers in silicon. A pulsed laser emission of up to a few mW of peak...
Relaxation of upper laser levels in terahertz silicon lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Zhukavin, Roman, Phillips, Jonathan, Carder, Damian, Hovenier, Niels, ...
Relaxation of lower exited states of group-V donors in silicon which serve as upper working states of intracenter silicon lasers has been experimentally determined. The measurements show that decay...
The effects of water and ice on LIBS signals and the detection of water on Mars (2008)
Rauschenbach, Isabelle, Lazic, Violetta, Pavlov, Sergey, Hübers, Heinz-Wilhelm, Jessberger, Elmar
ExoMars, ESA’s upcoming mission to Mars will include Laser-induced Breakdown Spectroscopy (LIBS) to analyse the elemental composition of Martian surface materials in the temperature range from...
Terahertz lasers based on nonlinear frequency conversion in silicon (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Böttger, Ute, Zhukavin, Roman, Shastin, Valery, Hovenier, Niels, ...
New principals to generate stimulated emission in terahertz frequency range from silicon doped by shallow donor centers have been demonstrated. Lasing in the frequency bands of 1.2 – 1.8 THz; 2.5...
THz lasing of shallow donors in stressed silicon crystals (2008)
Shastin, Valery, Zhukavin, Roman, Kovalevsky, Konstantin, Tsyplenkov, Veniamin, Pavlov, Sergey, Hübers, Heinz-Wilhelm
Results of experimental and theoretical study of terahertz stimulated emission from optically excited group-V donors (phosphor P, antimony Sb, arsenic As, bismuth Bi) in uniaxially stressed and...
THz amplification based on impurity-and transitions in Si/GeSi heterostructures (2008)
Shastin, Valery, Zhukavin, Roman, Bekin, Nickolay, Tsyplenkov, Veniamin, Radamson, Henry, Pavlov, Sergey, ...
Terahertz stimulated emission based on impurity-band optical transitions of phosphor donor centers embedded in Si/GeSi heterostructures is reported. THz emission was measured from selectively doped...
High-resolution molecular spectroscopy with 2.5 THz quantum cascade lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Greiner-Bär, Michael, Richter, Heiko, Mahler, Lukas, Tredicucci, Alessandro, ...
Quantum cascade lasers operating at about 2.5 terahertz have been implemented in a spectrometer for high resolution molecular spectroscopy. Linewidth, frequency tunability and frequency stability of...
Hübers, Heinz-Wilhelm, Pavlov, S., Huß, R., Neumann, J., Rauschenbach, I., Jessberger, E.K.
ExoMars, ESA`s next mission to Mars, will include a scientific instrument which combines Raman spectroscopy with Laser induced breakdown spectroscopy (LIBS) for the comprehensive in-situ...
Bystrzejewski, M., Lange, H., Huczko, A., Baranowski, P., Hübers, Heinz-Wilhelm, Gemming, T., ...
Carbon nanospheres with diameters between 100 and 400 nm have been successfully synthesized via low-power laser-assisted pyrolysis of anthracene in a nitrogen atmosphere. The developed facile route...
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...
Laser Local Oscillators for Heterodyne Receivers beyond 2 Terahertz (2008)
Hübers, Heinz-Wilhelm, Richter, Heiko, Pavlov, Sergey, Semenov, Alexei, Tredicucci, Alessandro, Mahler, Lucas, ...
The design and performance of a local oscillator (LO) for an airborne terahertz heterodyne receiver is reported. The LO is based on a THz gas laser, which is transversely excited by radiation from a...
Raman terahertz Si:P and Si:Sb lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Böttger, Ute, Hovenier, Niels, Redlich, Britta, Van Buuren, Rene, ...
In the past few years significant progress has been made towards silicon-based lasers mainly due to new approaches in the infrared wavelength range, such as silicon nanocrystals, A-centre mediated...
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...
Terahertz Heterodyne Receivers (2008)
The state-of-the art of terahertz heterodyne receivers are reviewed. Emphasis is placed on front-end components such as mixers and local oscillators. The back-end technology is described to a lesser...
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...
Terahertz Raman laser based on silicon doped with phosphorus (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Böttger, Ute, Zhukavin, Roman, Shastin, Valery, Hovenier, Niels, ...
Raman-type stimulated emission at frequencies between 5.0 and 5.2 THz as well as between 6.1 and 6.4 THz has been realized in silicon crystals doped by phosphorus donors. The Raman laser operates at...
Multi-crystalline silicon as active medium for terahertz intracenter lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Abrosimov, Nickolay, Riemann, Helge, Gavrilenko, Ludmila, Antonov, Alexander
Stimulated emission at terahertz frequencies has been obtained from multi-crystalline silicon doped by phosphor under optical excitation by a mid-infrared laser. The silicon samples consist of grains...
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...
Temperature- and field-dependence of critical currents in NbN microbridges (2008)
Engel, Andreas, Bartolf, Holger, Schilling, Andreas, Ilin, Konstantin, Siegel, Michael, Semenov, Alexei, ...
We report measurements of the critical current of nano- and micrometer-sized NbN bridges as a function of temperature and magnetic eld. The bridges were fabricated from 4 to 10 nm thick, sputtered...
Ultra-thin NbN films on Si: crystalline and superconducting properties (2008)
Ilin, Konstantin, Schneider, R, Gerthsen, D, Engel, Andreas, Bartolf, Holger, Schilling, Andreas, ...
We present results on superconducting and crystalline properties of NbN films with a thickness smaller than 10 nm. The films were deposited using reactive magnetron sputtering on heated silicon...
Detektion verborgener Objekte mittels eines abbildenden Terahertz-Heterodynempfängers (2008)
Hübers, Heinz-Wilhelm, Böttger, Ute, Richter, Heiko, Semenov, Alexej
In diesem Artikel wird über ein abbildendes Heterodynspektrometer berichtet, das bei einer Frequenz von 0.8 THz arbeitet. Mit dem System ist es möglich, unter der Kleidung verborgene Objekte...
Mono- and Polycrystalline Silicon for Terahertz Intracenter Lasers (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Abrosimov, Nickolay, Riemann, Helge
The performance of optically pumped terahertz silicon lasers with active media made from mono- and polycrystalline silicon doped by phosphorus has been investigated. The polycrystalline silicon...
Silicon Doped with Lithium and Magnesium from the Melt for Terahertz Laser Application (2008)
Abrosimov, Nickolay, Nötzel, Natalia, Riemann, Helge, Irmscher, Klaus, Pavlov, Sergey, Hübers, Heinz-Wilhelm, ...
Silicon crystals, doped with moderate concentration of magnesium or lithium, have been grown for application as optically pumped donor silicon lasers for the terahertz spectral region. The pedestal...
Terahertz Emission from Phosphor Centers in SiGe and SiGe/Si Semiconductors (2008)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Abrosimov, Nickolay, Riemann, Helge, Radamson, Henry, Bekin, Nickolay, ...
Terahertz-range photoluminescence from silicon-germanium crystals and superlattices doped by phosphor has been studied under optical excitation by radiation from a mid-infrared CO2 laser at low...
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Preusker, Regina, Rauschenbach, Isabelle, Jessberger, Elmar K.
Methodical investigations of Martian analogue materials under simulated Martian conditions are carried out with a Laser Induced Breakdown Spectroscopy (LIBS) spectrometer at the DLR Institute of...
Laser induced breakdown spectroscopy of soils and rocks under martian conditions (2007)
Rauschenbach, Isabelle, Pavlov, Sergey G., Lazic, Violetta, Hübers, Heinz-Wilhelm, Jessberger, Elmar K.
The present work is based on the GENTNER project and is funded by German Aerospace Center DLR. Here we report new results of our studies for the Raman/LIBS instrument for ExoMars on the dependence of...
16 Pixel HEB Heterodyne Mixer Array for 2.5 THz (2007)
Drakinskiy, Vladimir, Cherednichenko, Sergey, Berg, Terese, Hübers, Heinz-Wilhelm, Semenov, Alexei, Baubert, Jean, ...
A 16 pixel heterodyne receiver for 2.5 THz has been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers...
Intermediate Frequency Bandwidth of a Hot-Electron Mixer: Comparison with Bolometric Models (2007)
Semenov, Alexei, Richter, Heiko, Pavlov, Sergey, Hübers, Heinz-Wilhelm, Il'in, Konstantin, Siegel, Michael, ...
The gain bandwidth of a superconducting NbN hot-electron mixer quasioptically coupled to radiation was evaluated in different operation conditions and compared to presently known bolometric mixer...
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...
Schwarzer, Horst, Börner, Anko, Fix, Andreas, Günther, Burkhard, Hübers, Heinz-Wilhelm, Raugust, Marc, ...
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,...
Spectral Sensistivity and Spectral Resolution of Superconducting Single-Photon Detectors (2007)
Haas, Philipp Moritz, Semenov, Alexei, Hübers, Heinz-Wilhelm, Beyer, Jörn, Kirste, Alexander, Schurig, Thomas, ...
Single photon detectors based on meanders from 5-nm thin B1 niobium nitride nanostrips show moderate spectral resolution along with the spectral cut-off of the quantum efficiency occurring in the...
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...
Silicon Stokes terahertz laser (2007)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Hovenier, Jacob Niels, Klaassen, Tjeerd Onno, Carder, Damian A., Phillips, P. Jonathan, ...
A Raman-type silicon laser at terahertz frequencies has been realized. Stokes-shifted stimulated emission has been observed from silicon crystals doped by antimony donors when optically excited by an...
Low-threshold terahertz Si:As laser (2007)
Pavlov, Sergey, Böttger, Ute, Hübers, Heinz-Wilhelm, Zhukavin, Roman, Kovalevsky, Konstantin, Tsyplenkov, Veniamin, ...
The optical threshold of terahertz intracenter arsenic-doped silicon lasers has been reduced by two orders of magnitude by applying a compressive force to the laser crystal. The Si:As lasers were...
Molecular Spectroscopy with TeraHertz Quantum Cascade Lasers (2007)
Hübers, Heinz-Wilhelm, Pavlov, S.G., Richter, H., Semenov, A., Mahler, L., Tredicucci, A., ...
We have implemented quantum cascade lasers (QCLs) operating at about 2.5 THz in a spectrometer for high resolution molecular spectroscopy. One QCL has a Fabry-Perot resonator while the other is a...
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...
Zhukavin, Roman, Tsyplenkov, Veniamin, Kovalesky, Konstantin, Shastin, Valery, Pavlov, Sergey, Böttger, Ute, ...
The effect of uniaxial stress on terahertz stimulated emission from phosphor and antimony donors in silicon excited by CO2 laser radiation was studied. The laser action originates from 2p0->1s(T2)...
Terahertz gain on shallow donor transitions in silicon (2007)
Zhukavin, R.Kh., Shastin, V.N., Hübers, Heinz-Wilhelm, Pavlov, S.G., Hovenier, J.N., Klaassen, T.O., ...
Small signal gain measurements of optically excited terahertz silicon lasers are reported. Two types of lasers, Si:P and Si:Bi, were investigated. They were optically excited with radiation from a...
GREAT: the German first light heterodyne instrument for SOFIA (2007)
Graf, Urs U., Heyminck, Stefan, Güsten, Rolf, Hartogh, Paul, Hübers, Heinz-Wilhelm, Stutzki, Jürgen, ...
Silicon donor and Stokes terahertz lasers (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Hovenier, Jacob Niels, Klaassen, Tjeerd Onno, Riemann, Helge, Abrosimov, Nickolay, ...
Two types of lasers based on hydrogen-like impurity-related transitions in bulk silicon operate at frequencies between 1 and 7 THz (wavelength range of 50–230 μm). These lasers operate under...
Detektion und Spektroskopie im Terahertz-Spektralbereich (2006)
Der Terahertz (THz) Spektralbereich (ca. 0,3-10THz, 1mm-30µm) liegt zwischen dem infraroten und dem Mikrowellenbereich. Er ist sowohl in technologischer Hinsicht als auch unter dem Aspekt der...
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...
Energieauflösung und spektrale Empfindlichkeit supraleitender Einzelphotonenzähler (2006)
Haas, Philipp Moritz, Semenov, Alexei, Hübers, Heinz-Wilhelm, Beyer, Jörn, Kirste, Alexander, Schurig, Thomas, ...
Hochempfindliche, ultraschnelle NbN-Einzelphotonenzähler, basierend auf der kurzzeitigen bias-stromunterstützten Ausbildung eines normal leitenden Bereichs (Hot-Spot) durch Photonenabsorption in...
Schnelle SQUID-basierte Ausleseelektronik für Nanostrukturierte Einzelphotonenzähler (2006)
Kirste, Alexander, Drung, Dietmar, Beyer, Jörn, Ruede, Frank, Aßmann, Cornelia, Peters, Margret, ...
Wir berichten über die Eigenschaften von rauscharmen, an der PTB entwickelten SQUID-Stromsensoren sowie deren Anwendung für die Auslesung von nanostrukturierten Hot-Spot-Detektoren. Die hierfür...
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...
High Resolution Gas Phase Spectroscopy with a Quantum Cascade Laser at 2.5 THz (2006)
Hübers, Heinz-Wilhelm, Pavlov, S.G., Richter, H., Semenov, A.D., Tredicucci, A., Mahler, L., ...
We have performed high resolution spectroscopy of rotational lines of 12CH316OH in a THz spectrometer based on a 2.5 THz distributed feedback quantum cascade laser (QCL). The absolute frequency was...
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,...
Hübers, Heinz-Wilhelm, Pavlov, S.G., Richter, H., Semenov, A.D., Mahler, L., Tredicucci, A., ...
The quantum cascade laser is a powerful, narrow linewidth, and continous wave source of terahertz radiation. The authors have implemented a distributed feedback device in a spectrometer for...
Stress-controlled phonon-impurity resonant interactions in terahertz silicon lasers (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Riemann, Helge, Bekin, Nikolay, Zhukavin, Roman, Shastin, Valery
Silicon terahertz lasers operate at frequencies between 1 THz and 7 THz under conditions of optical mid-infrared or far-infrared pumping and low lattice temperatures (‹30 K). The intracenter laser...
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...
Frequency tunability of the terahertz silicon laser by a magnetic field (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Kimmitt, Maurice F., Riemann, Helge, Shastin, Valery N.
By applying a magnetic field to the terahertz intracenter silicon laser the degeneracy of the donor states is lifted. In the case of a bismuth doped silicon laser operating at 6 THz it is...
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...
Terahertz Silicon Lasers (2006)
Hübers, Heinz-Wilhelm, Pavlov, S.G., Shastin, V.N.
Terahertz silicon lasers are based on intracenter transitions of group-V donors. The peculiarities due to electron-phonon interaction and the state-of-the-art performance such as frequency tunability...
Long wavelength response of unstressed and stressed Ge:Ga detectors (2006)
Hübers, Heinz-Wilhelm, Pavlov, S.G., Holldack, K., Schade, U., Wüstefeld, G.
Photoconductivity spectra of unstressed and stressed Ge:Ga detectors were measured. The ecperiments were performed with a polarizing step scan Fourier transform spectrometer using the synchrotron...
Heterodyne receiver at 2.5 THz with quantum cascade laser and hot electron bolometric mixer (2006)
Hübers, Heinz-Wilhelm, Pavlov, S.G., Richter, H., Semenov, A.D., Mahler, L., Tredicucci, A., ...
Quantum cascade lasers (QCLs) operating at 2.5 THz have been used for gas phase spectroscopy and as local oscillator in a heterodyne receiver. One QCL has a Fabry-Perot resonator while the other has...
GREAT: The German first light heterodyne instrument for SOFIA (2006)
Graf, Urs U., Heyminck, Stefan, Güsten, Rolf, Hartogh, Paul, Hübers, Heinz-Wilhelm, Jacobs, Karl, ...
GREAT, the German REceiver for Astronomy at Terahertz frequencies, is a first generation SOFIA dual channel heterodyne PI-instrument for high resolution spectroscopy. The system is developed by a...
Spectral characterization of a 2.5 THz multi-mode quantum cascade laser (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Richter, Heiko, Semenov, Alexei, Tredicucci, Alessandro, Köhler, Rüdeger, ...
Recently, terahertz-range semiconductor quantum cascade lasers (QCL) have attracted attention as potential local oscillators in heterodyne receivers. The basic characterization of the lasers, such as...
Silicon Donor and Stokes terahertz lasers (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Hovenier, Jacob Niels, Klaassen, Tjeerd Onno, Carder, Damian A., Phillips, P. Jonathan, ...
In the past few years significant progress has been made towards silicon-based lasers. Numerous approaches in the infrared wavelength range were elaborated to overcome the indirect bandgap structure...
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...
Active Terahertz Imaging for Security (2006)
Hübers, Heinz-Wilhelm, Ewert, Uwe, Hansen, K.P., Ritchie, D., Merkel, H., Nuscheler, F., ...
Suicide bombers and anonymous mail attacks have become serious threats word wide. Since X-ray is difficult to apply for personnel scans due to radiation safety regulations, new technologies for...
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...
Heterodyne Receiver at 2.5 THz with Quantum Cascade Laser and Hot Electron Bolometric Mixer (2006)
A quantum cascade laser (QCL) operating at 2.5 THz has been used for gas phase spectroscopy and as local oscillator in a heterodyne receiver. The linewidth and frequency tunability of the QCL have...
Stimulated Terahertz Stokes Emission of Silicon Crystals Doped with Antimony Donors (2006)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Hovenier, Jacob Niels, Klaassen, Tjeerd Onno, Carder, Damian A., Phillips, P. Jonathan, ...
Stimulated Stokes emission has been observed from silicon crystals doped by antimony donors when optically excited by radiation from a tunable infrared free electron laser. The photon energy of the...
GREAT: the German first light heterodyne instrument for SOFIA (2006)
Graf, Urs, Heyminck, Stefan, Güsten, Rolf, Hartogh, Paul, Hübers, Heinz-Wilhelm, Jacobs, Karl, ...
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...
Time domain analysis of coherent terahertz synchrotron radiation (2005)
Hübers, Heinz-Wilhelm, Semenov, A., Holldack, K., Schade, U., Wüstefeld, G., Gol'tsman, G.
The time structure of terahertz coherent synchrotron radiation (CSR) has been analyzed with a fast superconducting hot electron bolometer at the electron storage ring BESSY II. The emission from a...
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...
Hübers, Heinz-Wilhelm, Pavlov, Sergej G., Semenov, Alexei D., Köhler, R., Mahler, L., Tredicucci, A., ...
A quantum cascade laser operating at 2.5 THz has been investigated with respect to performance parameters which are relevant for a local oscillator in a heterodyne receiver. The beam profile has been...
High Resolution Atmospheric and Astronomic Sensing at THz Frequencies (2005)
The Terahertz (THz) part of the electromagnetic spectrum bears an amazing scientific potential in astronomy and atmospheric research. Many fundamental absorption and emission lines of astrophysical...
THz lasing from donor centers in uniaxially stressed silicon (2005)
Shastin, Valery N., Zhukavin, Roman Kh., Pavlov, Sergey, Hübers, Heinz-Wilhelm
Recent results of experimental and theoretical studies of THz stimulated emission from optically excited group-V shallow donor centers (P, Sb, As, Bi) in uniaxially stressed silicon are reviewed and...
Terahertz optically pumped silicon lasers (2005)
Pavlov, Sergey, Hübers, Heinz-Wilhelm, Hovenier, Jacob Niels, Klaassen, Tjeerd Onno, Carder, Damian A., Phillips, P. Jonathan, ...
Stimulated terahertz (THz) emission from silicon single crystals doped by group-V donors has been obtained by optical excitation with pulsed infrared lasers. Pumping by a conventional TEA CO2 laser...
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,...
1.8THz receiver development for the TELIS instrument (2005)
Mair, Ulrich, Suttiwong, Nopporn, Wagner, Georg, Birk, Manfred, Richter, H., Semenov, A.D., ...
A new state-of-the-art balloon borne three channel (500GHz, 625GHz, 1.8 THz) cryogenic heterodyne spectrometer will allow enhanced limb sounding of the Earth's atmosphere within the submillimeter and...
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...
Frequency Tunable Terahertz Silicon Laser (2005)
Hübers, Heinz-Wilhelm, Pavlov, Sergej G., Hovenier, J.N., Klaassen, T.O., Carder, D., Zhukavin, R.Kh., ...
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...
Semenov, Alexei, Engel, Andreas, Hübers, Heinz-Wilhelm, Ilin, Konstantin, Siegel, Michael
We have studied supercurrent-assisted formation of the resistive state in nano-structured Nb and NbN superconducting films after absorption of a single photon. In amorphous narrow NbN strips the...