[time-nuts] What’s the BEST crystal?

[Bob kb8tq]

Hi

> On Feb 29, 2020, at 3:23 PM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
> 
> --------
> 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 ?

…… and done with sapphire. 

This is the real answer to “why is nobody going to do this?”. You already
have something ( the sapphire resonators ) that does better than 
anything you could reasonably expect.

Bob



> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by incompetence.
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.