Nano-Kelvin thermometry and temperature control: Beyond the thermal noise limit
Date
2014
Authors
Weng, Wenle
Anstie, James
Stace, T M
Campbell, Geoff
Baynes, Fred N
Luiten, Andre
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American Physical Society
Abstract
We demonstrate thermometry with a resolution of 80nK/Hz using an isotropic crystalline whispering-gallery mode resonator based on a dichroic dual-mode technique. We simultaneously excite two modes that have a mode frequency ratio that is very close to two (±0.3ppm). The wavelength and temperature dependence of the refractive index means that the frequency difference between these modes is an ultrasensitive proxy of the resonator temperature. This approach to temperature sensing automatically suppresses sensitivity to thermal expansion and vibrationally induced changes of the resonator. We also demonstrate active suppression of temperature fluctuations in the resonator by controlling the intensity of the driving laser. The residual temperature fluctuations are shown to be below the limits set by fundamental thermodynamic fluctuations of the resonator material.
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Keywords
Keywords: Refractive index; Temperature distribution; Thermal expansion; Thermometers; Frequency differences; Residual temperature; Resonator materials; Temperature dependence; Temperature fluctuation; Temperature sensing; Thermodynamic fluctuations; Whispering-gal
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Source
Physical Review Letters
Type
Journal article
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Open Access
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