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Published on: August 2, 2019
Model for excess noise in voltage-biased superconducting bolometers
Applied Optics
|March 28, 2008
Summary
Superconducting transition-edge sensors achieve their thermal fluctuation limit, showing white noise for far-infrared and millimeter wave detection. Noise peaks at higher frequencies are understood and can be managed by material selection.
Area of Science:
- Physics
- Astrophysics
- Electrical Engineering
Background:
- Superconducting transition-edge sensors are crucial for sensitive detection of far-infrared and millimeter wavelengths.
- Optimizing thermal isolation and understanding noise sources are key challenges in bolometer development.
Purpose of the Study:
- To develop and characterize superconducting transition-edge bolometers for far-infrared and millimeter wave applications.
- To analyze the noise spectrum of these bolometers and identify dominant noise sources.
Main Methods:
- Fabrication of bolometers suspended by silicon nitride legs for thermal isolation.
- Measurement of noise spectra across a range of frequencies (200 mHz to 10-50 Hz).
- Detailed noise modeling incorporating thermal fluctuations and electrothermal feedback.
Main Results:
- Bolometers exhibited white noise at their thermal fluctuation limit (NEP ~10(-17) W/√Hz) at lower frequencies.
- A broad noise peak was observed at higher frequencies, attributed to complex thermal circuits and electrothermal feedback.
- Noise calculations accurately matched experimental data from three distinct device designs.
Conclusions:
- The developed bolometers demonstrate performance near the thermal fluctuation limit, suitable for sensitive astronomical observations.
- Understanding and modeling the high-frequency noise peak is critical for optimizing detector performance.
- Material selection offers a pathway to shift the noise peak away from the frequencies of interest for specific applications.
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