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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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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1204 | |||
| Permanent link to this record | |||||
| Author | Trifonov, A.; Tong, C.-Y. E.; Grimes, P.; Lobanov, Y.; Kaurova, N.; Blundell, R.; Goltsman, G. | ||||
| Title |
Development of a silicon membrane-based multipixel hot electron bolometer receiver | Type | Journal Article | ||
| Year | 2017 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 27 | Issue | 4 | Pages | 1-5 |
| Keywords | Multi-pixel, NbN HEB, silicon-on-insulator, horn array | ||||
| Abstract | We report on the development of a multipixel 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 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, fed by a monolithic drilled smooth-walled horn array. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1051-8223 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1324 | |||
| Permanent link to this record | |||||
| 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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| Notes | Approved | no | |||
| Call Number | RPLAB @ kovalyuk @ | Serial | 1111 | ||
| Permanent link to this record | |||||
| 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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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | 1439677 | Serial | 1464 | ||
| Permanent link to this record | |||||
| Author | Tong, C.-Y. E.; Trifonov, A.; Shurakov, A.; Blundell, R.; Gol’tsman, G. | ||||
| Title |
A microwave-operated hot-electron-bolometric power detector for terahertz radiation | Type | Journal Article | ||
| Year | 2015 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 25 | Issue | 3 | Pages | 2300604 (1 to 4) |
| Keywords | NbN HEB mixer | ||||
| Abstract | A new class of microwave-operated THz power detectors based on the NbN hot-electron-bolometer (HEB) mixer is proposed. The injected microwave signal ( 1 GHz) serves the dual purpose of pumping the HEB element and enabling the read-out of the internal state of the device. A cryogenic amplifier amplifies the reflected microwave signal from the device and a homodyne scheme recovers the effects of the incident THz radiation. Two modes of operation have been identified, depending on the level of incident radiation. For weak signals, we use a chopper to chop the incident radiation against a black body reference and a lock-in amplifier to perform synchronous detection of the homodyne readout. The voltage measured is proportional to the incident power, and we estimate an optical noise equivalent power of 5pW/ √Hz at 0.83 THz. At higher signal levels, the homodyne circuit recovers the stream of steady relaxation oscillation pulses from the HEB device. The frequency of these pulses is in the MHz frequency range and bears a linear relationship with the incident THz radiation over an input power range of 15 dB. A digital frequency counter is used to measure THz power. The applicable power range is between 1 nW and 1 μW. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1558-2515 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1354 | |||
| Permanent link to this record | |||||