[time-nuts] Pressure sensitivity of Rb vapor cell standards

[Magnus Danielson]

Hi,

Let's recall the action of the Rubidium lamp is to optically pump Rb87
to the right state, such that state-transition using the hyper-fine
transition can be observed with good S/N. This is done by excite Rb87
with the two D-lines 780 nm and 795 nm, but then use the Rb85 isotope to
consume the 795 nm transition energy. Further, this also reduces light
on the detector, reducing it's flicker noise.

Since the rubidium lamp transitions is fairly wide and that the Rb87
cell is heated and acceptance is also fairly wide-band, it works out
pretty well.

Maybe I should just take one of my 780 nm diodes and try in the cell
with broken Rb-lamp oscillator, just for fun.

Cheers,
Magnus

On 2020-02-18 18:56, Dana Whitlow wrote:
> What's the optimum wavelength for the Rb light source?  A laser would
> certainly have
> a much narrower linewidth than an LED, provided one can find a laser with
> the correct
> wavelength.  Many diode lasers have a detector integrated into the same
> package, making
> tightly-stabilized output power a snap to achieve.
>
> Also: at 60C is the vapor pressure of Rb high enough to work with vis-a-vis
> achieving a
> quality lock to the atomic transition?
>
> Dana
>
>
> On Tue, Feb 18, 2020 at 4:07 AM Attila Kinali <attila at kinali.ch> wrote:
>
>> On Mon, 17 Feb 2020 18:16:04 -0600
>> magnus <magnus at rubidium.se> wrote:
>>
>>> Hi,In the 5065 and most others, the light intensity is not stabilized.
>>> It should not be too hard to regulate the Rb lamp amplitude and servo
>>> it to light intensity from the detector. Didn't Poul-Henning check this?
>>
>> I still think, replacing the 5065 lamp with a 780nm LED would be worthwhile
>> to try. Yes, the LEDs have a broader spectrum than a lamp, but it is a lot
>> easier to keep it stable than a fluerescent lamp. It would also allow to
>> lower the temperature of the Rb cell to get to the zero tempco point (which
>> seems to be around 60°C for most mixtures).
>>
>>
>>                                 Attila Kinali
>>
>> --
>> It is upon moral qualities that a society is ultimately founded. All
>> the prosperity and technological sophistication in the world is of no
>> use without that foundation.
>>                  -- Miss Matheson, The Diamond Age, Neal Stephenson
>>
>> _______________________________________________
>> 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.
>>
> _______________________________________________
> 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.