[time-nuts] What does determine the short term stability of an Rb vapor cell standard?

[Attila Kinali]

On Sun, 25 Mar 2018 14:13:56 -0500
Dana Whitlow <k8yumdoober at gmail.com> wrote:

> Could it be that with the narrow-band laser emission the dip in
> light transmission of the Rb cell is significantly improved?   I know
> that diode lasers are generally not paragons of virtue when it comes
> to intensity noise, so I'm wondering what accounts for the claims of
> better SNR with laser illumination.

Those who use lasers, seem to mostly use a variant of saturated
absorption spectroscopy, to get a sub-Doppler lock. Ie the laser
is stabilized to a couple of 100Hz to a few kHz, at most.
(An alternative, that nobody seems to use would be to use DVALL,
which uses the the Zemann splitting to get a narrow line width)

Using that, you get a laser that is very close to the the real
absorption maximum of the vapor cell used, hence reducing light
shift variation due to detuning/wander of the laser wavelength.

As for intensity noise, yes, it's not glorious with lasers, but
most papers I've read have a stabilization for that as well, so
it gets attenuated a bit.

			Attila Kinali

-- 
<JaberWorky>	The bad part of Zurich is where the degenerates
                throw DARK chocolate at you.