it sounds like there's some kind of coupling, inductive or optoelectronic

but yes, I also want the juicy details!

so this is the clock

https://en.wikipedia.org/wiki/NIST-F1

or this

https://en.wikipedia.org/wiki/NIST-F2

or there's already F4 too, but it doesn't have a Wikipedia article yet

https://www.nist.gov/news-events/news/2025/04/new-atomic-fou...

but maybe they are talking about the new non-microwave clocks that use Ytterbium-based optical combs ...

or about the Aluminum ion clock

https://www.nist.gov/news-events/news/2025/07/nist-ion-clock...

mind blown