High fidelity state preparataion and measurement of ion qubits with spin I > 1/2

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 stroboscopicaly driving

strong and weak transitions. We demonstrate this method achieving a SPAM infidelity of < 1e-4,

allowing future systems to leverage naturally occurring isotopes with favorable wavelengths and

masses such as the 137Ba+ qubit used in this work. State preparation is performed by blending

standard, fast optical pumping using E1 transitions and narrow microwave or optical E2 transitions

addressing the extra states in the I=3/2 isotope of 137Ba+. Measurement is performed with repeated

coherent shelving to multiple metastable states.