[time-nuts] What’s the BEST crystal?

[Poul-Henning Kamp]

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In message <20200229210755.1abd900696f8aa85567d2151 at kinali.ch>, Attila Kinali writes:
>On Sat, 29 Feb 2020 13:44:59 -0500

>But, there is not much we can do about absorption/desorption.

Actually, there are things you can do, but they are very
expensive.

One of the early paths of experiments with optic fibers were
to replace the absorbed hydrogen with deuterium which is
slightly larger, in order to move the OH- absorption
peak away from the 1.3 micrometer band. (Bake at 1000°C
in a D2 atmosphere for a couple of hours).

Stuffing bigger atoms into the gaps that way will reduce the
opportunities for other atoms to squeeze in.

If you were *really* serious about it, you would start out growing
your quartz from monoisotopic silicon and oxygen, picking the smaller
silicon (28) and larger oxygen (18) in order to reduce the size
of the gaps to begin with.  It will probably also do wonders for
your Q that all bonds are identical.

>The diameter of the blank has to be scaled with its thickness, in
>order not to compromise the f*Q product. Which in turn makes it
>a bit problematic in terms of packaging, but nothing unsolvable.

Isn't that where "whispering gallery" modes come into the picture ?

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