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Proceedings Paper

Quantum-limited quasiparticle mixers at 100 GHz
Author(s): Carl A. Mears; Qing Hu; Paul L. Richards; A. Worsham; Daniel E. Prober; Antti V. Raisanen
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Paper Abstract

Accurate measurements have been made of the noise and gain of superconducting-insulating- superconducting (SIS) mixers employing small-area (1 micrometers 2) Ta/Ta2O5/Pb0.9Bi0.1 tunnel junctions. The authors have measured an added mixer noise of 0.61 +/- 0.31 quanta at 95.0 GHz, which is within 25% of the quantum limit of 0.5 quanta. A detailed comparison is made between theoretical predictions of the quantum theory of mixing and experimentally measured noise and gain. The authors used the shapes of I-V curves pumped at the upper and lower sideband frequencies to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment.

Paper Details

Date Published: 1 July 1991
PDF: 13 pages
Proc. SPIE 1477, Superconductivity Applications for Infrared and Microwave Devices II, (1 July 1991); doi: 10.1117/12.45612
Show Author Affiliations
Carl A. Mears, Univ. of California/Berkeley and Lawrence Berkeley Lab. (United States)
Qing Hu, Univ. of California/Berkeley and Lawrence Berkeley Lab. (United States)
Paul L. Richards, Univ. of California/Berkeley and Lawrence Berkeley Lab. (United States)
A. Worsham, Yale Univ. (United States)
Daniel E. Prober, Yale Univ. (United States)
Antti V. Raisanen, Helsinki Univ. of Technology (Finland)


Published in SPIE Proceedings Vol. 1477:
Superconductivity Applications for Infrared and Microwave Devices II
Vernon O. Heinen; Kul B. Bhasin, Editor(s)

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