Physics

Noise (video)

Analytical Chemistry (journal)

Image (mathematics)

Optics

Artificial intelligence

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Cryogenics

Chemistry

Materials science

Thermal

Computer science

Chromatography

Thermodynamics

Optics Letters

Mechanical loss of dielectric mirror coatings sets fundamental limits for both gravitational wave detectors and cavity-stabilized optical local oscillators for atomic clocks. Two approaches are used to determine the mechanical loss: ringdown measurements of the coating quality factor and direct measurement of the coating thermal noise. Here we report a systematic study of the mirror thermal noise from room temperature to 4 K by operating reference cavities at these temperatures. The directly measured thermal noise is used to extract the corresponding mechanical loss for SiO$_2$/Ta$_2$O$_5$ coatings, which are compared with previously reported values.

Thermal noise and mechanical loss of SiO2/Ta2O5 optical coatings at cryogenic temperatures