Phase-stable injection-locked laserat 674 nm for manipulating trappedstrontium ions

Sammanfattning

For optical qubit encoding, laser phase noise limits the coherence time for qubit manipulations.In this thesis, we address this challenge by replicating a low-phase-noise laser system for qubit manipulation of trapped ions in a cryogenic environment. Using injection locking technology, we inject a laser diode with another laser, ensuring the replicated light retains the same spectral properties. We describe the implementation of this technique, analyse its impact on the laser spectrum, and validate it by comparing its coherence time on a trapped-ion qubit with the previously used laser.Our results demonstrate that the new laser system preserves the coherence time achieved with the seed laser, with a qubit coherence time of $T_{coh}= \SI{2.52\pm0.15}{\milli\second} $, paving the way for scalable and robust quantum computing and simulation in the cryogenic setup. In the future, the laser phase noise may be further reduced by spectral filtering techniques with a narrowband optical cavity. This work contributes to overtake one of the key obstacles in trapped-ion quantum computation: having long qubit coherence time.