[time-nuts] HP5065B !!!

[Attila Kinali]

On Sun, 28 Apr 2013 14:36:16 +0200
Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

> On 04/28/2013 02:01 PM, Attila Kinali wrote:

> When being at NIST last summer, they had us tour the facility. One of 
> them was not as much a show but a physical lab. We got to trim up and 
> test laser-cooling of... rubidium vapour. It was about 100000 of 
> hardware on the table if I recall correctly, but nothing really advanced 
> really. A secondary rubidium cell was used as a detector for the right 
> rubidium features. Using that and tune two lasers with lock in 
> amplifiers also having sweep features, it became fairly simple to do. 
> More than half the table of equipment does not apply to a rubidium clock 
> anyway, so the set up could be rationalized down considerably.

Yes, it seems like it is fairly "easy". At least [3] and [4] give that
impression. 

> We succeeded to laser-cool both the Rb-87 and Rb-85 :)
> 
> Turned out that once you got about the right wavelengths and fairly 
> balanced polarization, much other things like the magnetic 
> field-strength was not very critical at all to achieve and maintain the 
> effect.

Yes, the magnetic field is there to provide an axis and orientation
for the atoms. As for polarisation, AFAIK most of the MOT experiments
use circular polarisation, to have an equal strength in all polarisation
directions (but i can be mistaken).

> It was a fun lab to do, and I wish to learn more about steering laser 
> wavelengths etc. I do far to little optical stuff.

Then [1] and [2] will be of interest to you :-)

> It is also interesting that our optically pumped rubidiums is in fact 
> more closely related to modern atomic standards than traditional caesium 
> beams. The fountains is really a cross of them both to some degree.

I thought about this as well. The principle of all atomic clocks is
to get some popuplation inversion which is then probed by a microwave
signal. Cs Beams and H-Masers use a magnetic fields to separate the
atoms with different spins and select the right ones to feed into
the cavity, while Rb and all optical clocks use light the electrons
and the higher probabilty that an electron will fall into the higher
state than in the lower state. I'm not exactly sure what a Cs fountain
does. But considering the lack of a state selection magnet, i guess they
are pumped by the laser light as well.


			Attila Kinali

[1] "Using diode lasers for atomic physics", by Wieman and Hollberg, 1990
http://web.mit.edu/kimt/www/nice_readings/wieman-diode-lasers.pdf

[2] "A narrow-band tunablediode laser system with gratingfeedback,
and a saturatedabsorptionspectrometerfor Cs and Rb", by MacAdam, et al, 1992
http://fisica.usach.cl/~iolivare/MacAdamSteinbachWieman92.pdf

[3] Inexpensive laser cooling and trapping experiment for undergraduate 
laboratories", by Wieman, Flowers and Gilbert, 1994
http://ajp.aapt.org/resource/1/ajpias/v63/i4/p317_s1

[4] "A simple laser cooling and trapping apparatus for undergraduate
laboratories" by Mellish and Wilson, 2002
http://ajp.aapt.org/resource/1/ajpias/v70/i9/p965_s1


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