[time-nuts] MIT 2 inch cesium fountain, optically pumped

Jim Lux jimlux at earthlink.net
Thu Nov 20 07:40:37 EST 2014

On 11/19/14, 9:17 PM, Magnus Danielson wrote:
> Hi Rick,
> They did not mention the complexity of the laser system they needed,
> especially considering that the optical bench of a fountain isn't all
> that small, and also because they want to de-tune lasers. While they
> seems to have an idea, they didn't touch on that subject.
> Nice to see that people think in a different way thought.
> Looking forward to see the progress on this one.
> Cheers,
> Magnus
> On 11/20/2014 05:24 AM, Richard (Rick) Karlquist wrote:
>> See:
>> http://newsoffice.mit.edu/2014/portable-atomic-clocks-1112
>> Any comments?

And, of course, the article being cited in the news release is behind a 

I'm always a bit cynical when I see the words like
"We have a path toward making a compact, robust clock that’s better than 
CSACs by a couple of orders of magnitude, and more stable over longer 
periods of time.”"
and "potentially the size of a Rubik’s cube."

That "path towards"....

Having watched the progress of the  SpaceClock/1 Liter Atomic Clock/Deep 
Space Atomic Clock (all names for the Hg ion clock).. it's a long long 
way from "concept sort of demonstrated in the lab" to "device I can buy 
with a large-ish check"

Just reading the abstract, which doesn't give much detail about how "lab 
bench" this is, I'm going to guess this is at TRL 3 - basic principle 
demonstrated on a lab bench.
The press release is talking about applications at TRL 8 or 9.  A 
finished product..

It's probably 20-30 years away, and getting from lab full of equipment 
to "Rubik's Cube" (i.e. a liter) is going to be a lot more challenging 
than those authors think, I suspect.

That said, it's neat to see folks pushing in different directions.

The other day I was down in a lab under my office and saw a "breadbox 
sized" unit that can cool some atoms down to 100 picoKelvins in a few 
seconds with the push of a button.

  And not too long ago(1995), that was lab full of gear and a team of 
researchers struggling for days to get it to sometimes, maybe work.


"The current experimental systems were designed by people with a 
tremendous amount of knowledge and experience in experimental atomic 
physics, and until now producing a BEC without expertise in ultracold 
atom trapping has been a daunting task" from

so, from
first demo in a lab in 1995 - which got them a Nobel
to cookbook for grad students and post docs and $300k in 2003
to one-off box that has a pushbutton and fits in a locker on ISS in 2015

http://coldatomlab.jpl.nasa.gov/news/CalTest/  has a picture of the box 
on the shaker table

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