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Gerecht E, Musante CF, Jian H, Zhuang Y, Yngvesson KS, Dickinson J, et al. Improved characteristics of NbN HEB mixers integrated with log-periodic antennas. In: Proc. 10th Int. Symp. Space Terahertz Technol.; 1999. p. 200–7.
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Gerecht E, Musante CF, Zhuang Y, Yngvesson KS, Gol’tsman GN, Voronov BM, et al. NbN hot electron bolometric mixerss—a new technology for low-noise THz receivers. IEEE Trans Appl Supercond. 1999;47(12):2519–27.
Abstract: New advances in hot electron bolometer (HEB) mixers have recently resulted in record-low receiver noise temperatures at terahertz frequencies. We have developed quasi-optically coupled NbN HEB mixers and measured noise temperatures up to 2.24 THz, as described in this paper. We project the anticipated future performance of such receivers to have even lower noise temperature and local-oscillator power requirement as well as wider gain and noise bandwidths. We introduce a proposal for integrated focal plane arrays of HEB mixers that will further increase the detection speed of terahertz systems.
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Gerecht E, Musante CF, Zhuang Y, Ji M, Yngvesson KS, Goyette T, et al. NbN hot electron bolometric mixer with intrinsic receiver noise temperature of less than five times the quantum noise limit. In: Proc. IMS. Vol 2.; 2000. p. 1007–10.
Abstract: In recent years, improvements in device development and quasi-optical coupling techniques utilizing planar antennas have led to a significant achievement in low noise receivers for the edges of the submillimeter frequency regime. Hot electron bolometric (HEB) receivers made of thin superconducting films such as NbN have produced a viable option for instruments designed to measure the molecular spectra for astronomical applications as well as in remote sensing of the atmosphere in the THz regime. This paper describes an NbN HEB mixer with intrinsic DSB receiver noise temperature of at most five times the quantum noise limit at frequencies as high as 2.24 THz
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Yngvesson KS, Gerecht E, Musante CF, Zhuang Y, Ji M, Goyette TM, et al. Low-noise HEB heterodyne receivers and focal plane arrays for the THz regime using NbN. In: Hwu RJ, Wu K, editors. Proc. SPIE. Vol 3795. SPIE; 1999. p. 357–68.
Abstract: We have developed prototype HEB receivers using thin film superconducting NbN devices deposited on silicon substrates. The devices are quasi-optically coupled through a silicon lens and a self-complementary log-specific toothed antenna. We measured DSB receiver noise temperatures of 500 K (13 X hf/2k) at 1.56 THz and 1,100 K (20 X hf/2k) at 2.24 THz. Noise temperatures are expected to fall further as devices and quasi-optical coupling methods are being optimized. The measured 3 dB IF conversion gain bandwidth for one device was 3 GHz, and it is estimated that the bandwidth over which the receiver noise temperature is within 3 dB of its minimum value is 6.5 GHz which is sufficient for a number of practical applications. We will discuss our latest results and give a detailed description of our prototype setup and experiments. We will also discuss our plans for developing focal plane arrays with tens of Hot Electron Bolometric mixer elements on a single silicon substrate which will make real time imaging systems in the THz region feasible.
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