Detection of ion micromotion in a linear Paul trap with a high finesse cavity.

We demonstrate minimization of ion micromotion in a linear Paul trap with the use of a high finesse cavity. The excess ion micromotion projected along the optical cavity axis or along the laser propagation direction manifests itself as sideband peaks around the carrier in the ion-cavity emission spectrum. By minimizing the sideband height in the emission spectrum, we are able to reduce the micromotion amplitude along two directions to approximately the spread of the ground state wave function.

Spectroscopy on a single trapped ¹³⁷Ba⁺ ion for nuclear magnetic octupole moment determination.

We present precision measurements of the hyperfine intervals in the 5D3/2 manifold of a single trapped Barium ion, ¹³⁷Ba⁺. Measurements of the hyperfine intervals are made between mF = 0 sublevels over a range of magnetic fields allowing us to interpolate to the zero field values with an accuracy below a few Hz, an improvement on previous measurements by three orders of magnitude. Our results, in conjunction with theoretical calculations, provide a 30-fold reduction in the uncertainty of the magnetic dipole (A) and electric quadrupole (B) hyperfine constants.