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| Author | Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Golts'man, G.; Gershenzon, E.; Voronov B. | ||||
| Title | Superconductive NbN hot-electron bolometric mixer performance at 250 GHz | Type | Conference Article | ||
| Year | 1996 | Publication | Proc. 7th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 7th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 331-336 | ||
| Keywords | NbN HEB mixers | ||||
| Abstract | Thin film NbN (<40 A) strips are used as waveguide mixer elements. The electron cooling mechanism for the geometry is the electron-phonon interaction. We report a receiver noise temperature of 750 K at 244 GHz, with / IF = 1.5 GHz, Af= 500 MHz, and Tphysical = 4 K. The instantaneous bandwidth for this mixer is 1.6 GHz. The local oscillator (LO) power is 0.5 1.tW with 3 dB-uncertainty. The mixer is linear to 1 dB up to an input power level 6 dB below the LO power. We report the first detection of a molecular line emission using this class of mixer, and that the receiver noise temperature determined from Y-factor measurements reflects the true heterodyne sensitivity. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 945 | |||
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| Author | Trifonov, A.; Tong, C.-Y. E.; Grimes, P.; Lobanov, Y.; Kaurova, N.; Blundell, R.; Goltsman, G. | ||||
| Title | Development of A Silicon Membrane-based Multi-pixel Hot Electron Bolometer Receiver | Type | Conference Article | ||
| Year | 2017 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 27 | Issue | 4 | Pages | 6 |
| Keywords | Multi-pixel, HEB, silicon-on-insulator, horn array | ||||
| Abstract | We report on the development of a multi-pixel Hot Electron Bolometer (HEB) receiver fabricated using silicon membrane technology. The receiver comprises a 2 × 2 array of four HEB mixers, fabricated on a single chip. The HEB mixer chip is based on a superconducting NbN thin film deposited on top of the silicon-on-insulator (SOI) substrate. The thicknesses of the device layer and handling layer of the SOI substrate are 20 μm and 300 μm respectively. The thickness of the device layer is chosen such that it corresponds to a quarter-wave in silicon at 1.35 THz. The HEB mixer is integrated with a bow-tie antenna structure, in turn designed for coupling to a circular waveguide, |
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| Call Number | RPLAB @ kovalyuk @ | Serial | 1111 | ||
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| Author | Trifonov, Andrey; Tong, C. Edward; Lobanov, Yury; Kaurova, Natalia; Blundell, Raymond; Gol’tsman, Gregory | ||||
| Title | An investigation of the DC and IF performance of silicon-membrane HEB mixer elements | Type | Conference Article | ||
| Year | 2015 | Publication | Proc. 26th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 26th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 40 | ||
| Keywords | silicon-membrane HEB waveguide mixer | ||||
| Abstract | We report on our initial development towards a 2x2 multi-pixel HEB waveguide mixer for operation at 1.4 THz. We have successfully fabricated devices comprising an NbN bridge integrated with antenna test structure using a silicon membrane as the supporting substrate. DC measurements of the test chips demonstrate critical current from 0.1 – 1mA depending on the size of device, with T c of around 10 K and ΔTc ~ 0.8 K. | ||||
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| Call Number | Serial | 1160 | |||
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| Author | Trifonov, A.; Tong, C.-Y. E.; Lobanov, Y.; Kaurova, N.; Blundell, R.; Goltsman, G. | ||||
| Title | Gap frequency and photon absorption in a hot electron bolometer | Type | Conference Article | ||
| Year | 2016 | Publication | Proc. 27th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 27th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 121 | ||
| Keywords | NbN HEB; Si membrane | ||||
| Abstract | The superconducting energy gap is a crucial parameter of a superconductor when used in mixing applications. In the case of the SIS mixer, the mixing process is efficient for frequencies below the energy gap, whereas, in the case of the HEB mixer, the mixing process is most efficient at frequencies above the gap, where photon absorption takes place more readily. We have investigated the photon absorption phenomenon around the gap frequency of HEB mixers based on NbN films deposited on silicon membranes. Apart from studying the pumped I-V curves of HEB devices, we have also probed them with microwave radiation, as previously described [1]. At frequencies far below the gap frequency, the pumped I-V curves show abrupt switching between the superconducting and resistive states. For the NbN HEB mixers we tested, which have critical temperatures of ~9 K, this is true for frequencies below about 400 GHz. As the pump frequency is increased beyond 400 GHz, the resistive state extends towards zero bias and at some point a small region of negative differential resistance appears close to zero bias. In this region, the microwave probe reveals that the device impedance is changing randomly with time. As the pump frequency is further increased, this random impedance change develops into relaxation oscillations, which can be observed by the demodulation of the reflected microwave probe. Initially, these oscillations take the form of several frequencies grouped together under an envelope. As we approach the gap frequency, the multiple frequency relaxation oscillations coalesce into a single frequency of a few MHz. The resultant square-wave nature of the oscillation is a clear indication that the device is in a bi-stable state, switching between the superconducting and normal state. Above the gap frequency, it is possible to obtain a pumped I-V curve with no negative differential resistance above a threshold pumping level. Below this pumping level, the device demonstrates bi-stability, and regular relaxation oscillation at a few MHz is observed as a function of pump power. The threshold pumping level is clearly related to the amount of power absorbed by the device and its phonon cooling. From the above experiment, we can derive the gap frequency of the NbN film, which is 585 GHz for our 6 μm thin silicon membrane-based device. We also confirm that the HEB mixer is not an efficient photon absorber for radiation below the gap frequency. 1. A. Trifonov et al., “Probing the stability of HEB mixers with microwave injection”, IEEE Trans. Appl. Supercond., vol. 25, no. 3, June 2015. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1204 | |||
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| Author | Tong, C. Edward; Trifonov, Andrey; Blundell, Raymond; Shurakov, Alexander; Gol’tsman, Gregory | ||||
| Title | A digital terahertz power meter based on an NbN thin film | Type | Abstract | ||
| Year | 2014 | Publication | Proc. 25th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 25th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 170 | ||
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | We have further studied the effect of subjecting a superconducting Hot Electron Bolometer (HEB) element made from an NbN thin film to microwave radiation. Since the photon energy is weak, the microwave radiation does not simply heat the film, but generates a bi-static state, switching between the superconducting and normal states, upon the application of a small voltage bias. Indeed, a relaxation oscillation of a few MHz has previously been reported in this regime [1]. Switching between the superconducting and normal states modulates the reflected microwave pump power from the device. A simple homodyne setup readily recovers the spontaneous switching waveform in the time domain. The switching frequency is a function of both the bias voltage (DC heating) and the applied microwave power. In this work, we use a 0.8 THz HEB waveguide mixer for the purpose of demonstration. The applied microwave pump, coupled through a directional coupler, is at 1 GHz. Since the pump power is of the order of a few μW, a room temperature amplifier is sufficient to amplify the reflected pump power from the HEB mixer, which beats with the microwave source in a homodyne set-up. After further amplification, the switching waveform is passed onto a frequency counter. The typical frequency of the switching pulses is 3-5 MHz. It is found that the digital frequency count increases with higher microwave pump power. When the HEB mixer is subjected to additional optical power at 0.8 THz, the frequency count also increases. When we vary the incident optical power by using a wire grid attenuator, a linear relationship is observed between the frequency count and the applied optical power, over at least an order of magnitude of power. This phenomenon can be exploited to develop a digital power meter, using a very simple electronics setup. Further experiments are under way to determine the range of linearity and the accuracy of calibration transfer from the microwave to the THz regime. References 1. Y. Zhuang, and S. Yngvesson, “Detection and interpretation of bistatic effects in NbN HEB devices,” Proc. 13 th Int. Symp. Space THz Tech., 2002, pp. 463–472. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1366 | |||
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| Author | Ryabchun, S.; Tong, C.-yu E.; Blundell, R.; Kimberk, R.; Gol’tsman, G. | ||||
| Title | Effect of microwave radiation on the stability of terahertz hot-electron bolometer mixers | Type | Conference Article | ||
| Year | 2006 | Publication | Proc. SPIE | Abbreviated Journal | Proc. SPIE |
| Volume | 6373 | Issue | Pages | 63730J (1 to 5) | |
| Keywords | NbN HEB mixers, hot-electron bolometer mixers, stability, Allan variance, LO power fluctuations | ||||
| Abstract | We report our studies of the effect of microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the NbN hot-electron bolometer (HEB) mixer incorporated into a THz heterodyne receiver. It is shown that exposing the HEB mixer to microwave radiation does not result in a significant rise of the receiver noise temperature and degradation of the mixer conversion gain so long as the level of microwave power is small compared to the local oscillator drive. Hence the injection of a small, but controlled amount of microwave radiation enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the stability of HEB mixer receivers. | ||||
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| Publisher | SPIE | Place of Publication | Editor | Anwar, M.; DeMaria, A.J.; Shur, M.S. | |
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| Area | Expedition | Conference | Terahertz Physics, Devices, and Systems | ||
| Notes | Approved | no | |||
| Call Number | Serial | 1441 | |||
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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 HEB mixer as a function of its RF embedding impedance | Type | Journal Article | ||
| Year | 2005 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 15 | Issue | 2 | Pages | 472-475 |
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | We have conducted an investigation of the optimal embedding impedance for a waveguide superconducting hot-electron bolometric (HEB) mixer. Three mixer chip designs for 800 GHz, offering nominal embedding resistances of 70 /spl Omega/, 35 /spl Omega/, and 15 /spl Omega/, have been developed. We used both High Frequency Structure Simulator (HFSS) software and scale model impedance measurements in the design process. We subsequently fabricated HEB mixers to these designs using 3-4 nm thick NbN thin film. Receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans were performed to determine the optimal combination of embedding impedance and normal-state resistance for a 50 Ohm IF load impedance. A receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer with normal state resistance of 62 /spl Omega/ incorporated into a circuit offering a nominal embedding impedance of 70 /spl Omega/. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to the embedding impedance of the mixer mount. | ||||
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| Notes | Approved | no | |||
| Call Number | 1439677 | Serial | 1464 | ||
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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 waveguide superconducting HEB mixer at different RF embedding impedances | 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 | 226-229 | ||
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | We have conducted an investigation of the performance of superconducting hot-electron bolometric (HEB) mixer at 800 GHz as a function of the embedding impedance of the waveguide embedding circuit. Using a single half-height mixer block, we have developed three different mixer chip configurations, offering nominal embedding resistances of 70, 35, and 15 Ohms. Both the High Frequency Structure Simulator (HFSS) software and scaled model impedance measurements were employed in the design process. Two batches of HEB mixers were fabricated to these designs using 3-4 nm thick NbN thin film. The mixers were characterized through receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans. Briefly, a minimum receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer of normal state resistance 62 Ohms incorporated into a circuit offering a nominal embedding impedance of 70 Ohms. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to that of the embedding impedance of the mixer mount. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1472 | |||
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| Author | Loudkov, D.; Tong, C.-Y. E.; Marrone, D. P.; Ryabchun, S.; Paine, S. N.; Blundell, R. | ||||
| Title | Transmission measurements of infrared filters for low-noise terahertz receiver 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 | 354-357 | ||
| Keywords | FTS, Zitex, alkali halide, crystalline quartz, Parylene, polyethylene, IR filters, transmission, THz applications | ||||
| Abstract | Infrared (IR) filters are very important to the efficient operation of cryogenic receivers. Usually, such filters are mounted on the radiation shield of the cryostat to reduce the heat load to the 4 K stage. Insufficient filtering may cause the temperature of the mixing element in a receiver to be excessively warm, leading to degradation in sensitivity. These filters should be effective in blocking the room temperature IR radiation from outside the cryostat, yet should be transparent across the desired signal frequency band. In the Terahertz frequency range, which is close to the infrared, it is difficult to find an inexpensive low- loss material that can provide the required IR blocking capacity. We present transmission measurements, made using a Fourier Transform Spectrometer (FTS), of a number of potential infrared filters between 0.4 and 1.6 THz. The filters tested include the widely-used, Teflon-based, Zitex-A and Zitex-G films, alkali halide based infrared filter, and crystalline quartz coated with Parylene, and polyethylene films. | ||||
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| Call Number | Serial | 1473 | |||
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| Author | Edward Tong, C.-Y.; Loudkov, Denis N.; Paine, Scott N.; Marrone, Dan P.; Blundell, Raymond | ||||
| Title | Vector measurement of the beam pattern of a 1.5 THz superconducting HEB receiver | 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 | 453-456 | ||
| Keywords | NbTiN HEB mixers | ||||
| Abstract | Near-field vector beam pattern of the 1.5 THz superconducting Hot Electron Bolometer (HEB) receiver currently in operation in Northern Chile has been performed in our laboratory. Using an open waveguide probe, we have mapped both the amplitude and phase of the beam emerging from our 1.5 THz HEB receiver package, across a number of planes along the line of propagation of the radio-beam. With an integration time of about 100 ms per point, a signal-to-noise ratio of about 25 dB was achieved for a beam waist of 3.5 mm. These measurements have proved to be invaluable in achieving good alignment between the cryostat housing the HEB mixer and the remainder of the receiver and telescope optics. The accuracy of our beam measurement is estimated to be ±0.2 mm in position and ±5 arc minutes in angular displacement. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1474 | |||
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| Author | Tong, C.-Y. Edward; Meledin, Denis; Blundell, Raymond; Erickson, Neal; Kawamura, Jonathan; Mehdi, Imran; Gol'tsman, Gregory | ||||
| Title | A 1.5 THz hot-electron bolometer mixer operated by a planar diode-based local oscillator | Type | Abstract | ||
| Year | 2003 | Publication | Proc. 14th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 14th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 286 | ||
| Keywords | waveguide NbN HEB mixers | ||||
| Abstract | We describe a 1.5 THz heterodyne receiver based on a superconductin g hot-electron bolometer mixer, which is pumped by an all-solid-state local oscillator chain. The bolometer is fabricated from a 3.5 nm-thick niobium nitride film deposited on a quartz substrate with a 200 nm-thick magnesium oxide buffer layer. The bolometer measures 0.15 fun in width and 1.5 1..tm in length. The chip consisting of the bolometer and mixer circuitry is incorporated in a fixed-tuned waveguide mixer block with a corru g ated feed horn. The local oscillator unit comprises of a cascade of four planar doublers followin g a MMIC-based W-band power amplifier. The local oscillator is coupled to the mixer using a Martin-Puplett interferometer. The local oscillator output power needed for optimal receiver performance is approximately 1 to 2 11W, and the chain is able to provide this power at a number of frequency points between 1.45 and 1.56 THz. By terminating the rf input with room temperature and 77 K loads, a Y-factor of 1.11 (DSB) has been measured at a local oscillator frequency of 1.476 THz at 3 GHz intermediate frequency. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1501 | |||
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| Author | Blundell, R.; Kawamura, J. H.; Tong, C. E.; Papa, D. C.; Hunter, T. R.; Gol’tsman, G. N.; Cherednichenko, S. I.; Voronov, B. M.; Gershenzon, E. M. | ||||
| Title | A hot-electron bolometer mixer receiver for the 680-830 GHz frequency range | Type | Conference Article | ||
| Year | 1998 | Publication | Proc. 6-th Int. Conf. Terahertz Electron. | Abbreviated Journal | Proc. 6-th Int. Conf. Terahertz Electron. |
| Volume | Issue | Pages | 18-20 | ||
| Keywords | NbN HEB mixers | ||||
| Abstract | We describe a heterodyne receiver designed to operate in the partially transparent atmospheric windows centered on 680 and 830 GHz. The receiver incorporates a niobium nitride thin film, cooled to 4.2 K, as the phonon-cooled hot-electron mixer element. The double sideband receiver noise, measured over the frequency range 680-830 GHz, is typically 700-1300 K. The instantaneous output bandwidth of the receiver is 600 MHz. This receiver has recently been used at the SubMillimeter Telescope, jointly operated by the Steward Observatory and the Max Planck Institute for Radioastronomy, for observations of the neutral carbon and CO spectral lines at 810 GHz and at 806 and 691 GHz respectively. Laboratory measurements on a second mixer in the same test receiver have yielded extended high frequency performance to 1 THz. | ||||
| Address | Leeds, UK | ||||
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| Publisher | IEEE | Place of Publication | Editor | ||
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ISBN | 0-7803-4903-2 | Medium | ||
| Area | Expedition | Conference | IEEE Sixth International Conference on Terahertz Electronics Proceedings. THZ 98. (Cat. No.98EX171) | ||
| Notes | Approved | no | |||
| Call Number | Serial | 1581 | |||
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| Author | Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Gol'tsman, G.; Gershenzon, E.; Voronov, B. | ||||
| Title | NbN hot-electron mixer measurements at 200 GHz | Type | Conference Article | ||
| Year | 1995 | Publication | Proc. 6th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 6th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 254-261 | ||
| Keywords | NbN HEB mixers | ||||
| Abstract | 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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| Notes | Approved | no | |||
| Call Number | Serial | 1626 | |||
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