English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We study the vacuum-induced degradation of high-finesse optical cavities withmirror coatings composed of SiO$_2$-Ta$_{2}$O$_{5}$ dielectric stacks, andpresent methods to protect these coatings and to recover their initial qualityfactor. For separate coatings with reflectivities centered at 370 nm and 422nm, a vacuum-induced continuous increase in optical loss occurs if thesurface-layer coating is made of Ta$_{2}$O$_{5}$, while it does not occur if itis made of SiO$_2$. The incurred optical loss can be reversed by filling thevacuum chamber with oxygen at atmospheric pressure, and the recovery rate canbe strongly accelerated by continuous laser illumination at 422 nm. Both thedegradation and the recovery processes depend strongly on temperature. We findthat a 1 nm-thick layer of SiO$_2$ passivating the Ta$_{2}$O$_{5}$ surfacelayer is sufficient to reduce the degradation rate by more than a factor of 10,strongly supporting surface oxygen depletion as the primary degradationmechanism.

Preventing and Reversing Vacuum-Induced Optical Losses in High-Finesse Tantalum (V) Oxide Mirror Coatings