optical clock system for testing fundamental symmetries -Optimization of an ultra-stable optical cavity-

We want to experimentally investigate the so far unexplored ²S_1/2  -  ²F_7/2  electric octupole (E3) transition in singly-charged ytterbium 173. The deformed 173 nucleus will cause hyperfine-induced dipole contributions to the nHz-wide E3 transition. This essentially eliminates a major shortcoming of the 171-based E3 clock, i.e., the pronounced probe light induced AC Stark shift. Furthermore, motional heating in ion traps during the interrogation process can lead to significant clock errors due to 2nd order Doppler shifts and DC Stark shifts. We characterize these shifts for various sequences and identify an interrogation protocol which cancels, to first order, the combined effects of the Stark and Doppler shifts with an engineered probe-induced light shift.