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Author |
Tol, J. van; Brunel, L.-C.; Wylde, R. J. |
Title |
A quasioptical transient electron spin resonance spectrometer operating at 120 and 240 GHz |
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Journal Article |
Year |
2005 |
Publication |
Rev. Sci. Instrum. |
Abbreviated Journal |
Rev. Sci. Instrum. |
Volume |
76 |
Issue |
7 |
Pages |
074101 (1 to 8) |
Keywords |
Schottky, noise temperature |
Abstract |
A new multifrequency quasioptical electron paramagnetic resonance (EPR) spectrometer is described. The superheterodyne design with Schottky diode mixer/detectors enables fast detection with subnanosecond time resolution. Optical access makes it suitable for transient EPR (TR-EPR) at 120 and 240 GHz. These high frequencies allow for an accurate determination of small g-tensor anisotropies as are encountered in excited triplet states of organic molecules like porphyrins and fullerenes. The measured concentration sensitivity for continuous-wave (cw) EPR at 240 GHz and at room temperature without cavity is 1013 spins/cm3 (15 nM) for a 1 mT linewidth and a 1 Hz bandwidth. With a Fabry-Perot cavity and a sample volume of 30 nl, the sensitivity at 240 GHz corresponds to [approximate]3×109 spins for a 1 mT linewidth. The spectrometer's performance is illustrated with applications of transient EPR of excited triplet states of organic molecules, as well as cw EPR of nitroxide reference systems and a thin film of a colossal magnetoresistance material. |
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Actually, noise spectral density is given (3e-19 W/Hz) |
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588 |
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Men’shchikov, E. M.; Gogidze, I. G.; Sergeev, A. V.; Elant’ev, A. I.; Kuminov, P. B.; Gol’tsman, G. N.; Gershenzon, E. M. |
Title |
Superconducting fast detector based on the nonequilibrium inductance response of a film of niobium nitride |
Type |
Journal Article |
Year |
1997 |
Publication |
Tech. Phys. Lett. |
Abbreviated Journal |
Tech. Phys. Lett. |
Volume |
23 |
Issue |
6 |
Pages |
486-488 |
Keywords |
NbN KID |
Abstract |
A new type of fast detector is proposed, whose operation is based on the variation of the kinetic inductance of a superconducting film caused by nonequilibrium quasiparticles created by the electromagnetic radiation. The speed of the detector is determined by the rate of multiplication of photo-excited quasiparticles, and is nearly independent of the temperature, being less than 1 ps for NbN. Models based on the Owen-Scalapino scheme give a good description of the experimentally determined dependence of the power-voltage sensitivity of the detector on the modulation frequency. The lifetime of the quasiparticles is determined, and it is shown that the reabsorption of nonequilibrium phonons by the condensate has a substantial effect even in ultrathin NbN films 5 nm thick, and results in the maximum possible quantum yield. A low concentration of equilibrium quasiparticles and a high quantum yield result in a detectivity D*=1012 W−1·Hz1/2 at a temperature T=4.2 K and D*=1016 W−1·cm· Hz1/2 at T=1.6 K. |
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1063-7850 |
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1593 |
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Gol’tsman, G.; Okunev, O.; Chulkova, G.; Lipatov, A.; Dzardanov, A.; Smirnov, K.; Semenov, A.; Voronov, B.; Williams, C.; Sobolewski, R. |
Title |
Fabrication and properties of an ultrafast NbN hot-electron single-photon detector |
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Journal Article |
Year |
2001 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
Volume |
11 |
Issue |
1 |
Pages |
574-577 |
Keywords |
NbN SSPD, SNSPD |
Abstract |
A new type of ultra-high-speed single-photon counter for visible and near-infrared wavebands based on an ultrathin NbN hot-electron photodetector (HEP) has been developed. The detector consists of a very narrow superconducting stripe, biased close to its critical current. An incoming photon absorbed by the stripe produces a resistive hotspot and causes an increase in the film’s supercurrent density above the critical value, leading to temporary formation of a resistive barrier across the device and an easily measurable voltage pulse. Our NbN HEP is an ultrafast (estimated response time is 30 ps; registered time, due to apparatus limitations, is 150 ps), frequency unselective device with very large intrinsic gain and negligible dark counts. We have observed sequences of output pulses, interpreted as single-photon events for very weak laser beams with wavelengths ranging from 0.5 /spl mu/m to 2.1 /spl mu/m and the signal-to-noise ratio of about 30 dB. |
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1558-2515 |
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1547 |
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Somani, S.; Kasapi, S.; Wilsher, K.; Lo, W.; Sobolewski, R.; Gol’tsman, G. |
Title |
New photon detector for device analysis: Superconducting single-photon detector based on a hot electron effect |
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Journal Article |
Year |
2001 |
Publication |
J. Vac. Sci. Technol. B |
Abbreviated Journal |
J. Vac. Sci. Technol. B |
Volume |
19 |
Issue |
6 |
Pages |
2766-2769 |
Keywords |
NbN SSPD, SNSPD |
Abstract |
A novel superconducting single-photon detector (SSPD), intrinsically capable of high quantum efficiency (up to 20%) over a wide spectral range (ultraviolet to infrared), with low dark counts (<1 cps), and fast (<40 ps) timing resolution, is described. This SSPD has been used to perform timing measurements on complementary metal–oxide–semiconductor integrated circuits (ICs) by detecting the infrared light emission from switching transistors. Measurements performed from the backside of a 0.13 μm geometry flip–chip IC are presented. Other potential applications for this detector are in telecommunications, quantum cryptography, biofluorescence, and chemical kinetics. |
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0734211X |
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1542 |
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Semenov, Alexei D.; Hübers, Heinz-Wilhelm; Richter, Heiko; Smirnov, Konstantin; Gol'tsman, Gregory N.; Voronov, Boris M. |
Title |
Superconducting hot-electron bolometer mixer for terahertz heterodyne receivers |
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Abstract |
Year |
2004 |
Publication |
Proc. 15th Int. Symp. Space Terahertz Technol. |
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Proc. 15th Int. Symp. Space Terahertz Technol. |
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Issue |
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Pages |
164 |
Keywords |
NbN HEB mixers |
Abstract |
A number of on-going astronomical and atmospheric research programs are aimed to the Terahertz (THz) spectral region. At frequencies above about 1.4 THz heterodyne receivers planned for these missions will use superconducting hot-electron bolometers as a mixers. We present current results on the development of superconducting NbN hot- electron bolometer mixer and quasioptical radiation coupling scheme for GREAT (German Receiver for Astronomy at Terahertz Frequencies, to be used aboard of SOFIA) and TELIS (Terahertz Limb Sounder). The mixer is incorporated into hybrid antenna consisting of a planar feed antenna, which has either logarithmic spiral or double-slot configuration, and hyperhemispherical silicon lens. For the log-spiral feed antenna, the double side-band receiver noise temperature of 5500 K was achieved at 4.3 THz. The noise temperature shows less than 3 dB increase in the intermediate frequency band from 4 GHz to 7 GHz. The hybrid antenna had almost frequency independent and symmetric radiation pattern with the beam-width slightly broader than expected for a diffraction limited pattern. Results of FTS measurements in the direct detection regime agreed with the spectral dependence of the noise temperature for spiral antennas with different spacing of inner terminals. |
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1492 |
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