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Doi Y, Wang Z, Ueda T, Nickels P, Komiyama S, Patrashin M, et al. CSIP – a novel photon-counting detector applicable for the SPICA far-infrared instrument. SPICA. 2009;(SPICA Workshop 2009).
Abstract: We describe a novel GaAs/AlGaAs double-quantumwell device for the infrared photon detection, called ChargeSensitive Infrared Phototransistor (CSIP). The principle of CSIP detector is the photo-excitation of an intersubband transition in a QW as an charge integrating gate and the signal ampli<ef><ac><81>cation by another QW as a channel with very high gain, which provides us with extremely high responsivity (104 – 106 A/W). It has been demonstrated that the CSIP designed for the mid-infrared wavelength (14.7 μm) has an excellent sensitivity; the noise equivalent power (NEP) of 7 × 10-19 W/ with the quantum effciency of ~ 2%. Advantages of the CSIP against the other highly sensitive detectors are, huge dynamic range of > 106, low output impedance of 103 – 104 Ohms, and relatively high operation temperature (> 2 K). We discuss possible applications of the CSIP to FIR photon detection covering 35 – 60 μm waveband, which is a gap uncovered with presently available photoconductors.
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Mitin V, Antipov A, Sergeev A, Vagidov N, Eason D, Strasser G. Quantum Dot Infrared Photodetectors: Photoresponse Enhancement Due to Potential Barriers. Nanoscale res lett. 2011;6(1):6.
Abstract: Potential barriers around quantum dots (QDs) play a key role in kinetics of photoelectrons. These barriers are always created, when electrons from dopants outside QDs fill the dots. Potential barriers suppress the capture processes of photoelectrons and increase the photoresponse. To directly investigate the effect of potential barriers on photoelectron kinetics, we fabricated several QD structures with different positions of dopants and various levels of doping. The potential barriers as a function of doping and dopant positions have been determined using nextnano3 software. We experimentally investigated the photoresponse to IR radiation as a function of the radiation frequency and voltage bias. We also measured the dark current in these QD structures. Our investigations show that the photoresponse increases ~30 times as the height of potential barriers changes from 30 to 130 meV.
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Kawakami A, Saito S, Hyodo M. Fabrication of nano-antennas for superconducting Infrared detectors. IEEE Trans. Appl. Supercond.. 2011;21(3):632–5.
Abstract: To improve the response performance of superconducting infrared detectors, we have developed a fabrication process for nano-antennas. A nano-antenna consists of a dipole antenna, and a superconducting thin film strip placed in the antenna's center. By measuring the transition temperature of the superconducting strips, we confirmed that their superconductivity maintained a good condition after the nano-antenna fabrication process. We also evaluated nano-antenna characteristics using Fourier transform infrared spectroscopy. The evaluated antenna length and width were respectively set at around 2400 nm and 400 nm, and the antennas were placed at intervals of several micrometers around the area of 1 mm2 . In an evaluation of spectral transmission characteristics, clear absorption caused by antenna effects was observed at around 1400 cm-1. High polarization dependencies were also observed.
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Lobanov Y, Shcherbatenko M, Shurakov A, Rodin AV, Klimchuk A, Nadezhdinsky AI, et al. Heterodyne detection at near-infrared wavelengths with a superconducting NbN hot-electron bolometer mixer. Opt. Lett.. 2014;39(6):1429–32.
Abstract: We report on the development of a highly sensitive optical receiver for heterodyne IR spectroscopy at the communication wavelength of 1.5 μm (200 THz) by use of a superconducting hot-electron bolometer. The results are important for the resolution of narrow spectral molecular lines in the near-IR range for the study of astronomical objects, as well as for quantum optical tomography and fiber-optic sensing. Receiver configuration as well as fiber-to-detector light coupling designs are discussed. Light absorption of the superconducting detectors was enhanced by nano-optical antennas, which were coupled to optical fibers. An intermediate frequency (IF) bandwidth of about 3 GHz was found in agreement with measurements at 300 GHz, and a noise figure of about 25 dB was obtained that was only 10 dB above the quantum limit.
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Beck M, Klammer M, Rousseau I, Gol’tsman GN, Diamant I, Dagan Y, et al. Probing superconducting gap dynamics with THz pulses. In: CLEO. Optical Society of America; 2015. SM3H.3 (1 to 2).
Abstract: We studied superconducting gap dynamics in a BCS superconductor NbN and electron doped cuprate superconductor PCCO following excitation with near-infrared (NIR) and narrow band THz pulses. Systematic studies on PCCO imply very selective electron-phonon coupling.
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