Compact acousto-optic deflector-based beam steering system for individual addressing of trapped ion qubits

The trapped-ion system emerges as a highly promising platform for quantum computing, distinguished by its minimal susceptibility to SPAM errors, prolonged coherence time, and superior fidelity in entangling gates. Enabling a scalable computing architecture with all-to-all connectivity necessitates the crucial requirement of individually addressing each trapped-ion qubit in a chain. Recent advancements have showcased diverse techniques for individual addressing, including the deployment of MEMS mirrors [1,2], multi-channel acousto-optic modulators (AOMs) [3], and integrated fiber arrays [4]. However, these approaches are not without their respective drawbacks. MEMS mirrors, for instance, impose constraints on laser power, while AOMs and fiber arrays encounter challenges related to the uniform spacing of ion chains and inevitable crosstalk.

In this context, our work introduces a compact individual addressing system leveraging four acousto-optic deflectors (AODs). This system affords improved addressing flexibility, increased laser power, and reduced crosstalk, thereby facilitating the realization of high-fidelity gates within a long ion chain. Measured results include a demonstrated addressing capability of up to 30 ions, with expected crosstalk levels below 0.1%. Furthermore, we envision achieving at least two times faster entangling gates than our current MEMS mirror steering system [2]. Additionally, our approach incorporates miniaturized optical components with minimal degrees of freedom, contributing to the development of a compact system characterized by minimal optical path length. This design choice enhances the system's resilience against external vibrations, solidifying its potential for practical quantum computing applications.