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Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Recent progress on photon-counting superconducting detectors for submillimeter astronomy

John D. Teufel, Thomas R. Stevenson, W.‐T. Hsieh, Mary J. Li, K. W. Rhee, Carl M. Stahle, Edward J. Wollack, A. Aassime, Per Delsing, Paula Wahlgren, D. E. Prober, Robert J. Schoelkopf

Published Feb 1, 2003• 3 citations
Publisher

Abstract

We are developing superconducting direct detectors for submillimeter astronomy that can in principle detect individual photons. These devices, Single Quasiparticle Photon Counter (SQPC), operate by measuring the quasiparticles generated when single Cooper-pairs are broken by absorption of a submillimeter photon. This photoconductive type of device could yield high quantum efficiency, large responsivity, microsecond response times, and sensitivities in the range of 10-20 Watts per root Hertz. The use of antenna coupling to a small absorber also suggests the potential for novel instrument designs and scalability to imaging or spectroscopic arrays. We will describe the device concept, recent results on fabrication and electrical characterization of these detectors, issues related to saturation and optimization of the device parameters. Finally, we have developed practical readout amplifiers for these high-impedance cryogenic detectors based on the Radio-Frequency Single-Electron Transistor (RF-SET). We will describe results of a demonstration of a transimpedance amplifier based on closed-loop operation of an RF-SET, and a demonstration of a wavelength-division multiplexing scheme for the RF-SET. These developments will be a key ingredient in scaling to large arrays of high-sensitivity detectors.

DOI
10.1117/12.459712

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We are developing superconducting direct detectors for submillimeter astronomy that can in principle detect individual photons. These devices, Single Quasiparticle Photon Counter (SQPC), operate by measuring the quasiparticles generated when single Cooper-pairs are broken by absorption of a submillimeter photon. This photoconductive type of device could yield high quantum efficiency, large responsivity, microsecond response times, and sensitivities in the range of 10-20 Watts per root Hertz. The use of antenna coupling to a small absorber also suggests the potential for novel instrument designs and scalability to imaging or spectroscopic arrays. We will describe the device concept, recent results on fabrication and electrical characterization of these detectors, issues related to saturation and optimization of the device parameters. Finally, we have developed practical readout amplifiers for these high-impedance cryogenic detectors based on the Radio-Frequency Single-Electron Transistor (RF-SET). We will describe results of a demonstration of a transimpedance amplifier based on closed-loop operation of an RF-SET, and a demonstration of a wavelength-division multiplexing scheme for the RF-SET. These developments will be a key ingredient in scaling to large arrays of high-sensitivity detectors.
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We extend the concept of the superconducting quantum counter in order to develop a new quantum detector for submillimeter astronomy. The detector exploits a cumulative detection mechanism, in which the response appears due to successive formation of the normal spot and a resistive domain in a narrow strip carrying sub-critical supercurrent. The intrinsic recovery time of the counter is partly determined by diffusion of nonequilibrium electrons and, thus, depends on the energy of detected photons. Depending on the superconducting material used and operation conditions, such detector may have cut-off wavelengths for the single-photon regime ranging from terahertz waves to visible light and simultaneously provide a moderate energy resolution. We simulated performance of the background-limited submillimeter direct detector from Ti having the 100-micrometer cut-off wavelength, low dark count rate and intrinsic 10-21 W Hz-1/2 noise equivalent power for 4-K background radiation. We present first results obtained with a detector prototype fabricated from ultra-thin Nb film.
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