Ba+ Optical Clock

Although the clock transition at 1762 nm has a very large BBR shift, the atomic properties of Ba+ are very well known. Consequently we can use Ba+ a calibration tool for our Lu+ clock. Most notably, the ground state g-factor has been measured to an inaccuracy of 10-8, and dominant matrix elements determining the clock polarizability are well known. This means Ba+ can be used to calibrate applied electromagnetic fields.

Such calibrations will allow us to:

  • Measure the g-factors of the clock levels in Lu+. This will ultimately provide accurate assessment of the sensitivity of the lutetium clock transitions to ac magnetic fields.
  • Calibrate rf-magnetic fields arising from currents induced in the trap electrodes by the rf confinement voltages.
  • Provide an in situ calibration of laser intensity. Through subsequent ac-stark shift measurements of the lutetium clock transitions, this will allow improvement in the corresponding polarizabilities.