Re: OT: Atomic nucleus excited with laser: a breakthrough after decades

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.
 
Thanks,
 
Joe Gwinn