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| Author | Khosropanah, Pourya | ||||
| Title | NbN and NbTiN hot electron bolometer THz mixers | Type | Book Whole | ||
| Year | 2003 | Publication | Chalmers University of Technology | Abbreviated Journal | |
| Volume | Issue | Pages | |||
| Keywords | HEB mixer, hot electron bolometer mixer, NbN, NbTiN, superconducting detector, heterodyne receiver, THz mixer, submillimeter mixer, quasioptical receiver, double slot antenna, twin slot antenna, spiral antenna, receiver noise, FTS, Fourier Transform Spectrometer | ||||
| Abstract | The thesis reports the development of Hot Electron Bolometer (HEB) mixers for radio astronomy heterodyne receivers in THz frequency range. Part of this work is the fabrication of HEB devices, which are based on NbN or NbTiN superconducting thin films (â‰<a4>5 nm). They are integrated with wideband spiral or double-slot planar antennas. The mixer chips are incorporated into a quasi-optical receiver. The experimental part of this work focuses on the characterization of the receiver as a whole, and the HEB mixers as a part. Double side band receiver noise temperature and the IF bandwidth are reported for frequencies from 0.7 THz up to 2.6 THz. The spectrum of the direct response of HEB integrated with dierent antennas are measured using Fourier Transform Spectrometer (FTS). The effect of the bolometer size on total receiver performance and the LO power requirements is also discussed. A high-yield and reliable process for fabrication of NbN HEB mixers have been achieved. Over 100 devices with different bolometer geometry, film property and also different antennas have been fabricated and measured. The measured data enables us to discuss the impact of different parameters to the receiver overall performance. This work has provided NbN HEB mixers to the following receivers: TREND (Terahertz REceiver with NbN HEB Device) operating at 1.25-1.5 THz, installed in AST/RO Submillimeter Wave Telescope, Amundsen/Scott South Pole Station, in 2002-2003. Band 6-low (1.410-1.700 THz) and 6-high (1.700-1.920 THz) of the HIFI (Heterodyne Instrument for Far Infra-red) in the Herschel Space Observatory, due to launch in 2007 by ESA (European Space Agency). Besides, there has been continuous efforts to develop better models to explain the mixer performance more accurately. They are based on two temperature model for electrons and phonons and solving one-dimensional heat balance equations along the bolometer. The principles of these models are illustrated and the calculated results are compared with measured data. |
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Ph.D. thesis | |||
| Publisher | Chalmers University of Technology | Place of Publication | Göteborg | Editor | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | ISBN | Medium | |||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 910 | |||
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| Author | Hajenius, M.; Baselmans, J. J. A.; Gao, J. R.; Klapwijk, T. M.; de Korte, P. A. J.; Voronov, B.; Gol'tsman, G. | ||||
| Title | Low noise NbN superconducting hot electron bolometer mixers at 1.9 and 2.5 THz | Type | Journal Article | ||
| Year | 2004 | Publication | Supercond. Sci. Technol. | Abbreviated Journal | Supercond. Sci. Technol. |
| Volume | 17 | Issue | 5 | Pages | S224-S228 |
| Keywords | NbN HEB mixers | ||||
| Abstract | NbN phonon-cooled hot electron bolometer mixers (HEBs) have been realized with negligible contact resistance between the bolometer itself and the contact structure. Using a combination of in situ cleaning of the NbN film and the use of an additional superconducting interlayer of a 10 nm NbTiN layer between the Au of the contact structure and the NbN film superior noise temperatures have been obtained as low as 950 K at 2.5 THz and 750 K at 1.9 THz. Here we address in detail the DC characterization of these devices, the interface transparencies between the bolometers and the contacts and the consequences of these factors on the mixer performance. | ||||
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| ISSN | 0953-2048 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 558 | |||
| Permanent link to this record | |||||
| Author | Baselmans, J.; Kooi, J.; Baryshev, A.; Yang, Z. Q.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Voronov, B.; Gol’tsman, G. | ||||
| Title | Full characterization of small volume NbN HEB mixers for space applications | Type | Conference Article | ||
| Year | 2005 | Publication | Proc. 16th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 16th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 457-462 | ||
| Keywords | NbN HEB mixers | ||||
| Abstract | NbN phonon cooled HEB’s are one of the most promising bolometer mixer technologies for (near) future (space) applications. Their performance is usually quantified by mea- suring the receiver noise temperature at a given IF frequency, usually around 1 – 2 GHz. However, for any real applications it is vital that one fully knows all the relevant properties of the mixer, including LO power, stability, direct detection, gain bandwidth and noise bandwidth, not only the noise temperature at low IF frequencies. To this aim we have measured all these parameters at the optimal operating point of one single, small volume quasioptical NbN HEB mixer. We find a minimum noise temperature of 900 K at 1.46 THz. We observe a direct detection effect indicated by a change in bias current when changing from a 300 K hot load to a 77 K cold load. Due to this effect we overestimate the noise temperature by about 22% using a 300 K hot load and a 77 K cold load. The LO power needed to reach the optimal operating point is 80 nW at the receiver lens front, 59 nW inside the NbN bridge. However, using the isothermal technique we find a power absorbed in the NbN bridge of 25 nW, a difference of about a factor 2. We obtain a gain bandwidth of 2.3 GHz and a noise bandwidth of 4 GHz. The system Allan time is about 1 sec. in a 50 MHz spectral bandwidth and a deviation from white noise integration (governed by the radiometer equation) occurs at 0.2 sec., which implies a maximum integration time of a few seconds in a 1 MHz bandwidth spectrometer. | ||||
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| Publisher | Place of Publication | Göteborg, Sweden | Editor | ||
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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 363 | |||
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| Author | Finkel, M. I.; Maslennikov, S. N.; Vachtomin, Yu. B.; Svechnikov, S. I.; Smirnov, K. V.; Seleznev, V. A.; Korotetskaya, Yu. P.; Kaurova, N. S.; Voronov, B. M.; Gol'tsman, G. N. | ||||
| Title | Hot electron bolometer mixer for 20 – 40 THz frequency range | Type | Conference Article | ||
| Year | 2005 | Publication | Proc. 16th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 16th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 393-397 | ||
| Keywords | IR NbN HEB mixers | ||||
| Abstract | The developed HEB mixer was based on a 5 nm thick NbN film deposited on a GaAs substrate. The active area of the film was patterned as a 30×20 μm 2 strip and coupled with a 50 Ohm coplanar line deposited in situ. An extended hemispherical germanium lens was used to focus the LO radiation on the mixer. The responsivity of the mixer was measured in a direct detection mode in the 25÷64 THz frequency range. The noise performance of the mixer and the directivity of the receiver were investigated in a heterodyne mode. A 10.6 μm wavelength CW CO 2 laser was utilized as a local oscillator. | ||||
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| Publisher | Place of Publication | Göteborg, Sweden | Editor | ||
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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 369 | |||
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| Author | Loudkov, D.; Tong, C. Y. E.; Blundell, R.; Kaurova, N.; Grishina, E.; Voronov, B.; Gol'tsman, G. | ||||
| Title | An investigation of the performance of the superconducting HEB슠mixer as a function of its RF슠embedding impedance | Type | Journal Article | ||
| Year | 2005 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | |
| Volume | 15 | Issue | 2 | Pages | 472-475 |
| Keywords | HEB mixer | ||||
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| Publisher | IEEE | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | Serial | 371 | |||
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