On Thu, 09 May 2024 17:56:06 -0400, Joe Gwinn <
joegwinn@comcast.net>
wrote:
On Thu, 09 May 2024 14:26:12 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs >><pcdhSpamMeSenseless@electrooptical.net> wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
[snip]
The cleverest part of the Hall-Haensch comb generator is that you can lock
the blue end of the comb to the second harmonic of the red end, one tooth >>>>> off, and lock the difference to a good reference. Then all the teeth have >>>>> the same phase noise as the reference oscillator, rather than 20 log(600 >>>>> THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.
Hmm. It had to be true, but I never connected the dots there. What
is mechanism by which this is achieved? References?
Thanks,
Joe Gwinn
Don’t have the reference handy, but the basic idea is to use a modelocked >>>system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use >>>fiber/grating pulse compression to bring that down to a few femtoseconds, >>>followed by a holey fiber to broaden the spectrum to more than an octave. >>>
Jan Hall is one of the best instruments guys ever.
I'll poke around his publications. He's bound to have left tracks.
The best source I've found so far is:
Optical and microwave metrology with frequency combs
Tara Fortier
NIST Time and Frequency Division
Oct 10, 2023
And
COMMUNICATIONS PHYSICS | (2019)2:153 | >https://doi.org/10.1038/s42005-019-0249-y | www.nature.com/commsphys
These are open access.
Joe Gwinn
The gory details are in:
"Optical frequency synthesis based on mode-locked lasers",
Rev. Sci. Instrum., Vol. 72, No. 10, October 2001
Cundiff, Ye, and Hall
DOI: 10.1063/1.1400144
ResearchGate has it.
Joe Gwinn
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