Maslennikov SN, Morozov DV, Ozhegov RV, Smirnov KV, Okunev OV, Gol’tsman GN. Imaging system for submillimeter wave range based on AlGaAs/GaAs hot electron bolometer mixers. In: Proc. 5-th MSMW. Vol 2.; 2004. p. 558–60.
Abstract: Electromagnetic radiation of the submillimeter (SMM) range is dispersed and absorbed significantly less than infrared (IR) radiation when passing through different objects. That is the reason for the development of an SMM imaging system. In this paper, we discuss the design of an SMM heterodyne imager, based on a matrix of AlGaAs/GaAs heterostructure hot electron bolometer mixers (HEB) with relatively high (about 77 K) operating temperature. The predicted double side band (DSB) noise temperature is about 1000 K and optimal local oscillator (LO) power is about 1 /spl mu/W for such mixers, which seems to be quite prospective for an SMM heterodyne imager.
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Sobolewski R, Verevkin A, Gol’tsman GN. Superconducting optical single-photon detectors. In: CLEO/QELS. Optical Society of America; 2004. IThD1.
Abstract: We review the development of superconducting single-photon detectors. The devices are characterized by experimental quantum efficiency of ~8% for infrared photons, counting rate ~2 GHz, 18 ps jitter, and <0.01 per second dark counts.
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Cherednichenko S, Khosropanah P, Berg T, Merkel H, Kollberg E, Drakinskiy V, et al. Optimization of HEB mixer for the Herschel Space Observatory [abstract]. In: Proc. 15th Int. Symp. Space Terahertz Technol.; 2004. 16.
Abstract: A mixer development for the HIFI instrument of the Herschel Space Observatory has come to the final stage. In our paper and conference presentation we will describe the most important details of the Band 6 Low and High Mixer Unit design. Special attention will be given to the optimization of the hot- electron bolometer mixer chip, which is based on 3.5nm NbN superconducting film on silicon. As the HEB’s local oscillator power requirements depend on the bolometer size, we have compared mixer noise temperature for different bolometer width- to- length ratio. A trade- off between mixer performance and local oscillator power requirements results in the mixer units equipped with optimized mixer chips, providing the largest coverage of the Band6 RF band with the lowest possible receiver noise. A short account of the beam pattern measurements of Band6 mixers will be given as well.
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Baselmans JJA, Hajenius M, Gao JR, Baryshev A, Kooi J, Klapwijk TM, et al. Hot electron bolometer mixers with improved interfaces: sensitivity, LO power and stability. In: Proc. 15th Int. Symp. Space Terahertz Technol.; 2004. p. 17–24.
Abstract: We study twin slot antenna coupled NbN hot electron bolometer mixers with an improved contact structure and a small volume, ranging from 1 µm × 0.1 µm to 2 × 0.3 µm. We obtain a DSB receiver noise temperature of 900 K at 1.6 THz and 940 K at 1.9 THz. To explore the practical usability of such small HEB mixers we evaluate the LO power requirement, the sensitivity and the stability. We find that the LO power requirement of the smallest mixers is reduced to about 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5. The stability of these receivers is characterized using a measurement of the Allan Variance. We find an Allan time of 0.5 sec. in an 80 MHz bandwidth. A small increase in stability can be reached by using a higher bias at the expense of a significant amount of sensitivity. The stability is sufficient for spectroscopic applications in a 1 MHz bandwidth at a 1 Hz chopping frequency.
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Ryabchun S, Korneev A, Matvienko V, Smirnov K, Kouminov P, Seleznev V, et al. Superconducting single photon detectors array based on hot electron phenomena. In: Proc. 15th Int. Symp. Space Terahertz Technol.; 2004. p. 242–7.
Abstract: In this paper we propose to use time domain multiplexing for large format arrays of superconducting single photon detectors (SSPDs) of the terahertz, visible and infrared frequency ranges based on ultrathin superconducting NbN films. Effective realization of time domain multiplexing for SSPD arrays is possible due to a short electric pulse of the SSPD as response to radiation quantum absorption, picosecond jitter and extremely low noise equivalent power (NEP). We present experimental results of testing 2×2 arrays in the infrared waveband. The measured noise equivalent power in the infrared and expected for the terahertz waveband is 10 – 21 WHz -1/2 . The best quantum efficiency (QE) of SSPD is 50% at 1.3 µm wavelength.
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