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arXiv · 2011.05986

Thermal noise and mechanical loss of SiO$_2$/Ta$_2$O$_5$ optical coatings at cryogenic temperatures

John M Robinson·Eric Oelker·William R Milner·Dhruv Kedar·Wei Zhang·Thomas Legero·Dan G Matei·Sebastian Hafner·Fritz Riehle·Uwe Sterr·Jun Ye
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Abstract

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.

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John M Robinson, Eric Oelker, William R Milner, Dhruv Kedar, Wei Zhang, Thomas Legero, Dan G Matei, Sebastian Hafner, Fritz Riehle, Uwe Sterr, Jun Ye. 2020-11-11. Thermal noise and mechanical loss of SiO$_2$/Ta$_2$O$_5$ optical coatings at cryogenic temperatures. https://doi.org/10.1364/ol.413758

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