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Gol'tsman, G.; Kouminov, P.; Goghidze, I.; Gershenzon, E. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Nonequilibrium kinetic inductive response of YBCO thin films to low power laser pulses |
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Journal Article |
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Year |
1995 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
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Volume |
5 |
Issue |
2 |
Pages |
2591-2594 |
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YBCO HTS KID |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have discovered a transient nonequilibrium kinetic inductive voltage response of YBCO thin films to 20 ps pulses of YAG:Nd laser radiation with 0.63 /spl mu/m and 1.54 /spl mu/m wavelength. By increasing the sensitivity of the read-out system with 100 ps resolution time and diminishing the light intensity (fluence 0.1-2 /spl mu/J/cm/sup 2/) and transport current (density /spl les/10/sup 5/ A/cm/sup 2/) we were able to observe a peculiar bipolar signal form with nearly equal amplitudes for each sign. The integration of the kinetic inductive response over time gives the result which is qualitatively, of the same form as the response in the resistive and normal states: the nonequilibrium picosecond scale component is followed by the bolometric nanosecond component. The nonequilibrium response is interpreted as suppression of the order parameter by excess quasiparticles followed by a change both in resistance (for the resistive state) and in kinetic inductance (for the superconducting state). |
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1051-8223 |
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1621 |
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Huebers, H.-W.; Schubert, J.; Semenov, A.; Gol’tsman, G. N.; Voronov, B. M.; Gershenzon, E. M.; Schwaab, G. W. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
NbN phonon-cooled hot-electron bolometer as a mixer for THz heterodyne receivers |
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Conference Article |
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Year |
1999 |
Publication |
Proc. SPIE |
Abbreviated Journal |
Proc. SPIE |
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3828 |
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410-416 |
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NbN HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have investigated a phonon-cooled NbN hot electron bolometric (HEB) mixer in the frequency range from 0.7 THz to 5.2 THz. The device was a 3.5 nm thin film with an in- plane dimension of 1.7 X 0.2 micrometers 2 integrated in a complementary logarithmic spiral antenna. The measured DSB receiver noise temperatures are 1500 K, 2200 K, 2600 K, 2900 K, 4000 K, 5600 K and 8800 K. The sensitivity fluctuation, the long term stability, and the antenna pattern were measured and the suitability of the mixer for a practical heterodyne receiver is discussed. |
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Spie |
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Chamberlain, J.M. |
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Terahertz Spectroscopy and Applications II |
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1477 |
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Ekström, H.; Kollberg, E.; Yagoubov, P.; Gol'tsman, G.; Gershenzon, E.; Yngvesson, S. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Phonon cooled ultra thin NbN hot electron bolometer mixers at 620 GHz |
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Conference Article |
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Year |
1997 |
Publication |
Proc. 8th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 8th Int. Symp. Space Terahertz Technol. |
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29-35 |
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NbN HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have measured the noise performance and gain bandwidth of 35 A thin NbN hot-electron mixers integrated with spiral antennas on silicon substrate lenses at 620 GHz. A double-sideband receiver noise temperature less than 1300 K has been obtained with a 3 dB bandwidth of GHz. The gain bandwidth is 3.2 GHz. A lower noise temperature of 1100 K has been achieved with an improved set-up. The mixer output noise dominated by thermal fluctuations is about 50-60 K, and the SSB receiver and intrinsic conversion gain is about -18 and -12 dB, respectively. Without mismatch losses and excluding the loss from the beamsplitter, we expect to achieve a receiver noise temperature of less than 700 K. |
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1604 |
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Ekstörm, H.; Kollberg, E.; Yagoubov, P.; Gol'tsman, G.; Gershenzon, E.; Yngvesson, S. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Gain and noise bandwidth of NbN hot-electron bolometric mixers |
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Journal Article |
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Year |
1997 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
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Volume |
70 |
Issue |
24 |
Pages |
3296-3298 |
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Keywords |
NbN HEB mixers, conversion loss, conversion gain, U-factor technique |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have measured the noise performance and gain bandwidth of 35 Å thin NbN hot-electron mixers integrated with spiral antennas on silicon substrate lenses at 620 GHz. The best double-sideband receiver noise temperature is less than 1300 K with a 3 dB bandwidth of ≈5 GHz. The gain bandwidth is 3.2 GHz. The mixer output noise dominated by thermal fluctuations is 50 K, and the intrinsic conversion gain is about −12 dB. Without mismatch losses and excluding the loss from the beamsplitter, we expect to achieve a receiver noise temperature of less than 700 K. |
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279 |
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Ekström, H.; Kroug, M.; Belitsky, V.; Kollberg, E.; Olsson, H.; Goltsman, G.; Gershenzon, E.; Yagoubov, P.; Voronov, B.; Yngvesson, S. |
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Title |
Hot electron mixers for THz applications |
Type |
Conference Article |
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Year |
1996 |
Publication |
Proc. 30th ESLAB |
Abbreviated Journal |
Proc. 30th ESLAB |
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207-210 |
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NbN HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have measured the noise performance of 35 A thin NbN HEB devices integrated with spiral antennas on antireflection coated silicon substrate lenses at 620 GHz. From the noise measurements we have determined a total conversion gain of the receiver of—16 dB, and an intrinsic conversion of about-10 dB. The IF bandwidth of the 35 A thick NbN devices is at least 3 GHz. The DSB receiver noise temperature is less than 1450 K. Without mismatch losses, which is possible to obtain with a shorter device, and with reduced loss from the beamsplitter, we expect to achieve a DSB receiver noise temperature of less ‘than 700 K. |
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Noordwijk, Netherlands |
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Rolfe, E. J.; Pilbratt, G. |
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Submillimetre and Far-Infrared Space Instrumentation |
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1606 |
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Gerecht, E.; Musante, C. F.; Schuch, R.; Lutz, C. R.; Jr.; Yngvesson, K. S.; Mueller, E. R.; Waldivian, J.; Gol'tsman, G. N.; Voronov, B. M.; Gershenzon, E. M. |
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Title |
Hot electron detection and mixing experiments in NbN at 119 micrometer wavelength |
Type |
Conference Article |
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Year |
1995 |
Publication |
Proc. 6th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 6th Int. Symp. Space Terahertz Technol. |
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284-293 |
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NbN HEB mixers, detectors |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have performed preliminary experiments with the goal of demonstrating a Hot Electron Bolometric (HEB) mixer for a 119 micrometer wavelength (2.5 THz). We have chosen a NbN device of size 700 x 350 micrometers. This device can easily be coupled to a laser LO source, which is advantageous for performing a prototype experiment. The relatively large size of the device means that the LO power required is in the mW range; this power can be easily obtained from a THz laser source. We have measured the amount of laser power actually absorbed in the device, and from this have estimated the best optical coupling loss to be about 10 di . We are developing methods for improving the optical coupling further. Preliminary measurements of the response of the device to a chopped black-body have not yet resulted in a measured receiver noise temperature. We expect to be able to complete this measurement in the near future. |
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1629 |
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Svechnikov, S.; Gol'tsman, G.; Voronov, B.; Yagoubov, P.; Cherednichenko, S.; Gershenzon, E.; Belitsky, V.; Ekstrom, H.; Kollberg, E.; Semenov, A.; Gousev, Y.; Renk, K. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Spiral antenna NbN hot-electron bolometer mixer at submm frequencies |
Type |
Journal Article |
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Year |
1997 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
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Volume |
7 |
Issue |
2 |
Pages |
3395-3398 |
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NbN HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We have studied the phonon-cooled hot-electron bolometer (HEB) as a quasioptical mixer based on a spiral antenna designed for the 0.3-1 THz frequency band and fabricated on sapphire and high resistivity silicon substrates. HEB devices were produced from superconducting 3.5-5 nm thick NbN films with a critical temperature 10-12 K and a critical current density of approximately 10/sup 7/ A/cm/sup 2/ at 4.2 K. For these devices we reached a DSB receiver noise temperature below 1500 K, a total conversion loss of L/sub t/=16 dB in the 500-700 GHz frequency range, an IF bandwidth of 3-4 GHz and an optimal LO absorbed power of /spl sime/4 /spl mu/W. We experimentally analyzed various contributions to the conversion loss and obtained an RF coupling factor of about 5 dB, internal mixer loss of 10 dB and IF mismatch of 1 dB. |
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1051-8223 |
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1597 |
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Gousev, Y. P.; Semenov, A. D.; Goghidze, I. G.; Pechen, E. V.; Varlashkin, A. V.; Gol'tsman, G. N.; Gershenzon, E. M.; Renk, K. F. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Current dependent noise in a YBa2Cu3O7-δ hot-electron bolometer |
Type |
Journal Article |
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Year |
1997 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
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Volume |
7 |
Issue |
2 |
Pages |
3556-3559 |
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Keywords |
YBCO HTS HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We investigated the output noise of a YBa2Cu3O7-δ (YBCO) superconducting hot-electron bolometer (HEB) in a large frequency range (10 kHz to 8 GHz); the bolometer either consisted of a structured 50 nm thick YBCO film on LaAlO/sub 3/ or a 30 nm thick film on a MgO substrate. We found that flicker noise dominated at low frequencies (below 1 MHz), while at higher frequencies Johnson noise and a current dependent noise were the main noise sources. |
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1051-8223 |
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1592 |
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Gershenzon, E. M.; Gol'tsman, G. N.; Kagane, M. L. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Energy spectrum of acceptors in germanium and its response to a magnetic field |
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Journal Article |
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Year |
1977 |
Publication |
Sov. Phys. JETP |
Abbreviated Journal |
Sov. Phys. JETP |
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Volume |
45 |
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4 |
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769-776 |
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p-Ge, photoconductivity, energy spectrum, magnetic field |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We investigated the spectrum of the submillimeter photoconductivity of p-Ge at helium temperatures and the effects of a magnetic field up to 40 kOe on the spectrum. A large number of lines of transitions between the excited states of the acceptors was observed, some of the lines were identified, and the energies of a number of spectral levels B, Al, Ga, In, and TI in Ge were identified. The results are compared with calculations and with experimental data obtained from the spectra of the photoexcitation of the ground state of the impurities. Using one transition as an example, we discuss the splitting of the excited states of acceptors in the magnetic field and under uniaxial compression. |
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1727 |
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Heusinger, M. A.; Nebosis,R. S.; Schatz, W.; Renk, K. F.; Gol’tsman, G. N.; Karasik, B. S.; Semenov, A. D.; Gershenzon, E. M. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Temperature dependence of bolometric and non-bolometric photoresponse of a structured YBa2Cu3O7-δ thin film |
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Conference Article |
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1993 |
Publication |
Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences |
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Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences |
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112 |
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193-195 |
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YBCO HTS detectors |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We investigated the temperature dependence of the transient voltage photoresponse of a current biased structured YBa2Cu3O7−δ thin film in its transition temperature region, around 79 K. Both, picosecond nonbolometric and nanosecond bolometric response to ultrashort far-infrared laser pulses were found for frequencies between 25 cm−1 and 215 cm−1. We will discuss optimum conditions for radiation detection and present an analysis of the dynamical behaviour of excited high T c thin films. |
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Meissner, M.; Pohl, R. O. |
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Seventh International Conference, Cornell University, Ithaca, New York, August 3-7, 1992 |
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1663 |
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Semenov, A. D.; Gol’tsman, G. N.; Gogidze, I. G.; Sergeev, A. V.; Gershenzon, E. M.; Lang, P. T.; Renk, K. F. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Subnanosecond photoresponse of a YBaCuO thin film to infrared and visible radiation by quasiparticle induced suppression of superconductivity |
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Journal Article |
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1992 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
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60 |
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7 |
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903-905 |
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YBCO HTS detectors |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We observed subnanosecond photoresponse of a structured superconducting YBa2Cu3O7−δ thin film to infrared and visible radiation. We measured the voltage response of a current biased film (thickness 700 Å) in a resistive state to radiation pulses. From our results we conclude a response time of about 90 ps and a responsivity of about 4×1010 Ω/J. We attribute the response to Cooper pair breaking and suppression of the superconducting energy gap induced by nonequilibrium quasiparticles. |
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0003-6951 |
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1672 |
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Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Gol'tsman, G.; Gershenzon, E.; Voronov, B. |
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Title |
NbN hot-electron mixer measurements at 200 GHz |
Type |
Conference Article |
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Year |
1995 |
Publication |
Proc. 6th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 6th Int. Symp. Space Terahertz Technol. |
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Volume |
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254-261 |
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NbN HEB mixers |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
We present noise and gain measurements of resistively driven NbN hot-electron mixers near 200 GHz. The device geometry is chosen so that the dominant cooling process of the hot-electrons is their interaction with the lattice. Except for a single batch, the intermediate frequency cut-off of these mixer elements is – 3 700 MHz, and has shown little variation among other batches of devices. At 100 MHz we measured intrinsic mixer losses as low as —3 dB. We measured the noise temperatures at several intermediate frequencies, and for the best de- vice at 137 MHz with 20 MHz bandwidth, we measured 2000 K; using a low-noise first- stage amplifier at 1.5 GHz with 200 MHz bandwidth, the receiver noise temperature measured 2800 K. We estimate that the noise contribution from the mixer is 500 K and the total losses are —15 dB at 137 MHz. |
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Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. |
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Determination of the limiting mobility of a two-dimensional electron gas in AlxGa1-xAs/GaAs heterostructures and direct measurement of the energy relaxation time |
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1996 |
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Phys. Rev. B Condens. Matter. |
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Phys. Rev. B Condens. Matter. |
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53 |
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12 |
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R7592-R7595 |
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2DEG, AlGaAs/GaAs heterostructures |
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We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility. |
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PMID:9982274 |
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1612 |
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Semenov, A. D.; Hübers, H.–W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M. |
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Frequency dependent noise temperature of the lattice cooled hot-electron terahertz mixer |
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2000 |
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Proc. 11th Int. Symp. Space Terahertz Technol. |
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Proc. 11th Int. Symp. Space Terahertz Technol. |
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39-48 |
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NbN HEB mixers |
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We present the measurements and the theoretical model on the frequency dependent noise temperature of a lattice cooled hot electron bolometer (HEB) mixer in the terahertz frequency range. The experimentally observed increase of the noise temperature with frequency is a cumulative effect of the non-uniform distribution of the high frequency current in the bolometer and the charge imbalance, which occurs near the edges of the normal domain and contacts with normal metal. In addition, we present experimental results which show that the noise temperature of a HEB mixer can be reduced by about 30% due to a Parylene antireflection coating on the Silicon hyperhemispheric lens. |
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Semenov, A. D.; Hübers, H.-W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M. |
![goto web page (via DOI) doi](img/doi.gif)
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Design and performance of the lattice-cooled hot-electron terahertz mixer |
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2000 |
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J. Appl. Phys. |
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J. Appl. Phys. |
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88 |
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11 |
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6758-6767 |
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HEB mixer, charge imbalance, HF current distribution |
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We present the measurements and the theoreticalmodel of the frequency-dependent noise temperature of a superconductor lattice-cooled hot-electron bolometer mixer in the terahertz frequency range. The increase of the noise temperature with frequency is a cumulative effect of the nonuniform distribution of the high-frequency current in the bolometer and the charge imbalance, which occurs at the edges of the normal domain and at the contacts with normal metal. We show that under optimal operation the fluctuation sensitivity of the mixer is determined by thermodynamic fluctuations of the noise power, whereas at small biases there appears additional noise, which is probably due to the flux flow. We propose the prescription of how to minimize the influence of the current distribution on the mixer performance. |
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