High fidelity state preparation and measurement of ion qubits with spin I > ½.

We present a method of state preparation and measurement (SPAM) that is amenable to trapped ion hyperfine qubits with nuclear spins higher than I = 1/2. The ground states of these higher nuclear spin isotopes do not afford a simple frequency selective preparation scheme on a strong transition, this limitation is circumvented by stroboscopically driving strong and weak transitions. We demonstrate this method achieving a SPAM infidelity of < le -4, allowing future systems to leverage naturally occurring isotopes with favorable wavelengths and masses such as the Ba-137(+) qubit used in this work State preparation is performed by blending standard, fast optical pumping using El transitions and narrow microwave or optical E2 transitions addressing the extra states in the I=3/2 isotope of Ba-137(+) Measurement is performed with repeated coherent shelving to multiple metastable states.