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

[Dana Whitlow]

I'd love to hear the outcome of your experiment with the laser.

Dana


On Tue, Feb 18, 2020 at 12:19 PM Magnus Danielson <magnus at rubidium.se>
wrote:

> 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
> >>
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