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Slysz W, Wegrzecki M, Papis E, Gol'tsman GN, Verevkin A, Sobolewski R. A method of optimization of the NbN superconducting single-photon detector. Vol 36.; 2004.
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Schubert J, Semenov A, Hübers H-W, Gol'tsman G, Schwaab G, Voronov B, et al. Broad-band terahertz NbN hot-electron bolometric mixer. In: Inst. Phys. Conf. Vol 167.; 1999. p. 663–6.
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Lobanov YV, Vakhtomin YB, Pentin IV, Khabibullin RA, Shchavruk NV, Smirnov KV, et al. Characterization of the THz quantum cascade laser using fast superconducting hot electron bolometer. EPJ Web Conf. 2018;195:04004 (1 to 2).
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Kroug M, Yagoubov P, Gol'tsman G, Kollberg E. NbN quasioptical phonon cooled hot electron bolometric mixers at THz frequencies. In: Inst. Phys. Conf. Ser. Vol 1. Bristol; 1997. p. 405–8.
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Merkel HF, Yagoubov PA, Kroug M, Khosropanah P, Kollberg EL, Gol’tsman GN, et al. Noise temperature and absorbed LO power measurement methods for NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies. In: Proc. 28th European Microwave Conf. Vol 1.; 1998. p. 294–9.
Abstract: In this paper the absorbed LO power requirements and the noise performance of NbN based phonon-cooled hot electron bolometric (HEB) quasioptical mixers are investigated for RF frequencies in the 0.55-1.1 range The minimal measured DSB noise temperatures are about 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz and 1250 K at 1.1 THz. The increase in noise temperature at 1.1THz is attributed to water absorption. The absorbed LO power is measured using a calorimetric approach. The results are subsequently corrected for lattice heating. These values are compared to results of a novel one dimensional hot spot mixer models and to a more traditional isotherm method which tends to underestimate the absorbed LO power for small bias powers. Typically a LO power between 50nW and 100nW is needed to pump the device to the optimal operating point.
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Ryabchun S, Smirnov A, Pentin I, Vakhtomin Y, Smirnov K, Kaurova N, et al. Superconducting single photon detector integrated with optical cavity. In: Proc. MLPLIT. Modern laser physics and laser-information technologies for science and manufacture; 2011. p. 143–5.
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Maslennikova A, Larionov P, Ryabchun S, Smirnov A, Pentin I, Vakhtomin Y, et al. Noise equivalent power and dynamic range of NBN hot-electron bolometers. In: Proc. MLPLIT. Modern laser physics and laser-information technologies for science and manufacture; 2011. p. 146–8.
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Gol’tsman GN, Gershenzon EM. High speed hot-electron superconducting bolometer. In: Birch JR, Parker TJ, editors. Proc. SPIE. Vol 2104. SPIE; 1993. p. 181–2.
Abstract: Physical limitation of response time of a superconducting bolometer as well as the nature of non-equilibrium detection of radiation have been investigated for Al, Nb and NbN thin films in spectral range from submillimeter to near-infraredwavelengths [1,2]. In the case of ideal heat removal from the film with the f_‘. 100A thickness the detection mechanism is an electron heating effect that is not selective to radiation wavelength in a very broad range. The response time ofan electron heating bolometer is determined by an electron-phonon interaction time. This time is of about 10 ns, 0.5 ns and 20 ps for Al, Nb, and NbN correspondingly near the critical temperature of the superconducting film. Thesensitive area of the bolometer consists of a number of narrow strips (with awidth of 1µm) connected in parallel to contact pads; these pads together witha sapphire substrate and a ground plate represent the microstrip transmissionline with an impedance of 50 Q.
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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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Ryabchun SA, Tretyakov IV, Finkel MI, Maslennikov SN, Kaurova NS, Seleznev VA, et al. Fabrication and characterisation of NbN HEB mixers with in situ gold contacts. In: Proc. 19th Int. Symp. Space Terahertz Technol. Groningen, Netherlands; 2008. p. 62–7.
Abstract: We present our recent results of the fabrication and testing of NbN hot-electron bolometer mixers with in situ gold contacts. An intermediate frequency bandwidth of about 6 GHz has been measured for the mixers made of a 3.5-nm NbN film on a plane Si substrate with in situ gold contacts, compared to 3.5 GHz for devices made of the same film with ex situ gold contacts. The increase in the intermediate frequency bandwidth is attributed to additional diffusion cooling through the improved contacts, which is further supported by the its dependence on the bridge length: intermediate frequency bandwidths of 3.5 GHz and 6 GHz have been measured for devices with lengths of 0.35 μm and 0.16 μm respectively at a local oscillator frequency of 300 GHz near the superconducting transition. At a local oscillator frequency of 2.5 THz the receiver has offered a DSB noise temperature of 950 K. When compared to the previous result of 1300 K obtained at the same local oscillator frequency for devices fabricated with an ex situ route, such a low value of the noise temperature may also be attributed to the improved gold contacts.
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