[time-nuts] 88Sr+ ion-clock live stream

[Watson Ladd]

On Sat, Dec 7, 2019 at 1:29 PM Anders Wallin <anders.e.e.wallin at gmail.com>
wrote:

> In Cs my understanding is that a transition mF=0 to mF=0 transition is used
> - so it is insensitive to the magnetic field[1].
> There is no magnetic field insensitive component of the 88Sr+ clock
> transition (other optical clocks will vary!)
> See e.g. around page 10 here for an energy-level diagram:
> http://resource.npl.co.uk/docs/networks/time/meeting3/klein.pdf
>
> To measure 88Sr+ line-center (where there is no peak at nonzero B-field!)
> the mid-point between a Zeeman pair is a good approximation, but one gets
> rid of the electric quadrupole shift by measuring the center of three pairs
> of components and calculating line-center from that. The servo-loop will
> thus need to probe the left and right side of multiple peaks in sequence.
> Our pulse-sequence now does 100 probe-pulses in about 7 seconds. If we
> probe left/right side of three pars (twelve frequencies in total) the
> line-center can be computed about once per minute. The ultra-stable clock
> laser acting as local oscillator needs to maintain stability on its own
> during those 1-2 minutes.
>

How do you then divide down the optical frequency and shim with the
computed offset?