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Siddiqi I, Prober DE. Nb–Au bilayer hot-electron bolometers for low-noise THz heterodyne detection. Appl Phys Lett. 2004;84(8):1404.
Abstract: The sensitivity of present Nb diffusion-cooled hot-electron bolometer (HEB) mixers is not quantum limited, and can be improved by reducing the superconducting transition temperature TC. Lowering TC reduces thermal fluctuations, resulting in a decrease of the mixer noise temperature TM. However, lower TC mixers have reduced dynamic range and saturate more easily due to background noise. We present 30 GHz microwave measurements on a bilayer HEB system, Nb–Au, in which TC can be tuned with Au layer thickness to obtain the maximum sensitivity for a given noise background. These measurements are intended as a guide for the optimization of THz mixers. Using a Nb–Au mixer with TC = 1.6 K, we obtain TM = 50 K with 2 nW of local oscillator (LO) power. Good mixer performance is observed over a wide range of LO power and bias voltage and such a device should not exhibit saturation in a THz receiver.
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Slysz W, Wegrzecki M, Bar J, Grabiec P, Gol'tsman GN, Verevkin M, et al. NbN superconducting single-photon detectors coupled with a communication fiber. Vol 37.; 2004.
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Gao JR, Hajenius M, Baselmans JJA, Klapwijk TM, de Korte PAJ, Voronov B, et al. NbN hot electron bolometer mixers with superior performance for space applications. In: Armandillo E, Leone B, editors. Proc. Int. workshop on low temp. electronics. Noordwijk; 2004. p. 11–7.
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Maslennikov S, Vachtomin Y, Antipov S, Smirnov K, Kaurova N, Grishina E, et al. NbN HEB mixers for frequencies of 2.5 and 3.8 THz. In: Proc. Tenth All-Russian sceintific conference of student-physicists and young sceintists (VNKSF-10). Moscow; 2004.
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Goltsman G, Korneev A, Izbenko V, Smirnov K, Kouminov P, Voronov B, et al. Nano-structured superconducting single-photon detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2004;520(1-3):527–9.
Abstract: NbN detectors, formed into meander-type, 10×10-μm2 area structures, based on ultrathin (down to 3.5-nm thickness) and nanometer-width (down to below 100 nm) NbN films are capable of efficiently detecting and counting single photons from the ultraviolet to near-infrared optical wavelength range. Our best devices exhibit QE >15% in the visible range and ∼10% in the 1.3–1.5-μm infrared telecommunication window. The noise equivalent power (NEP) ranges from ∼10−17 W/Hz1/2 at 1.5 μm radiation to ∼10−19 W/Hz1/2 at 0.56 μm, and the dark counts are over two orders of magnitude lower than in any semiconducting competitors. The intrinsic response time is estimated to be <30 ps. Such ultrafast detector response enables a very high, GHz-rate real-time counting of single photons. Already established applications of NbN photon counters are non-invasive testing and debugging of VLSI Si CMOS circuits and quantum communications.
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Moore DP, Remedios JJ, Waterfall AM, Burgess A. Measuring halocarbons from the MIPAS instrument.; 2004.
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Alexandre Karpov, David Miller, Rice FR, Stern JA, Bruce Bumble, LeDuc HG, et al. Low-noise SIS mixer for far-infrared radio astronomy. In: Proc. SPIE. Vol 5498. Glasgow, Scotland, UK; 2004. p. 616–21.
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Hajenius M, Baselmans JJA, Gao JR, Klapwijk TM, de Korte PAJ, Voronov B, et al. Low noise NbN superconducting hot electron bolometer mixers at 1.9 and 2.5 THz. Supercond Sci Technol. 2004;17(5):S224–S228.
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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Koshelets VP. Integrated superconducting submm receivers.; 2004.
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Koshelets VP, Shitov SV, Dmitriev PN Ermakov A. B., Filippenko LV, Koryukin OV, Sobolev AS, et al. Integrated submillimeter and terahertz receivers with superconducting local oscillator [abstract]. In: Presanted at 8th International Workshop “From Andreev Reflection to the International Space Station”.; 2004.
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