Robust Optical Engineering for a Trapped Ion Quantum Computer

Abstract

Trapped ions are one of the leading platforms for the implementation of quantum information processing (QIP), exhibiting one of the highest reported quantum gate and measurement fidelities. The challenge for the platform now is to maintain these high quality operations while expanding the system size beyond the ∼10-30 qubits that are available in today’s devices. Currently we are near completion of the construction of our trapped ion quantum computer that will incorporate multiple isotopes of barium as qubits/qudits. Barium has several favourable properties that make it the ideal ion for QIP and the aim of our device in the near future is to develop this species into the premiere ion for QIP. The device in the future is hoped to serve as a cloud based resource for the Waterloo research community, fostering collaborations between algorithms, error correction and atomic physics researchers, that is ultimately hoped to expedite the development of trapped ion QIP. This thesis discusses the robust optical engineering that went into the construction of this trapped ion quantum computer. We describe the details of the continuous wave optical subsystems used for ion initialization, cooling, and measurements of the quantum states, including the imaging system used to collect ion fluorescence. In addition, this thesis discusses the unique individual addressing system that we have designed and built for performing single and two-qubit gates based on Raman transitions. With this system we attain a relative intensity crosstalk between neighbouring ions on the order of 1e−4. This is comparable to the best currently available implementations but our system provides additional optical frequency and phase control knobs that allow for more control over quantum simulation and computation experiments. Finally we will discuss the trap, its associated electronics and the vacuum system that houses our ions and atomic source.