Model for excess noise in voltage-biased superconducting bolometers

We are developing superconducting transition-edge bolometers for far-infrared and millimeter wavelengths. The bolometers described here are suspended by thin legs of silicon nitride for thermal isolation. At frequencies between 200 mHz and 10-50 Hz these devices show white noise at their thermal flu...

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Bibliographic Details
Published inApplied optics (2004) Vol. 40; no. 34; p. 6229
Main Authors Gildemeister, J M, Lee, A T, Richards, P L
Format Journal Article
LanguageEnglish
Published United States 01.12.2001
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Summary:We are developing superconducting transition-edge bolometers for far-infrared and millimeter wavelengths. The bolometers described here are suspended by thin legs of silicon nitride for thermal isolation. At frequencies between 200 mHz and 10-50 Hz these devices show white noise at their thermal fluctuation limit (NEP approximately 10(-17) W/ radicalHz). At higher frequencies a broad peak appears in the noise spectrum, which we attribute to a combination of thermal fluctuations in complex thermal circuits and electrothermal feedback. Detailed noise calculations fit the noise measured in three different devices that were specifically designed to test the model. We discuss how changes in bolometer materials can shift the noise peak above the frequency range of interest for most applications.
ISSN:1559-128X
DOI:10.1364/AO.40.006229