Large-scale programmable trapped ion hardware, featuring high gate fidelity and long coherence times, is promising for realizing a practical fault-tolerant quantum computer (FTQC). However, individual addressing (IA) methods, which are important for implementing programmable gates in near-term quantum devices, can lead to undesired errors between the target ions and neighboring ions. In this work, we present a low-crosstalk optical addressing system based on multiple optical objectives and acousto-optic deflectors (AODs) with a symmetrical configuration. Two counter-propagating Raman operation beams are both tightly focused, generating an overlapping spot with a waist radius of approximately 1\upmum, to address the target ion. As a result, IA crosstalk, characterized by Rabi rate crosstalk on the spectator ion, is measured to be 1.19(5)×10−3, with the two ions separated by approximately 5.5~\upmum. This low-crosstalk optical addressing system holds promise for high-fidelity entangling operations, and the symmetrically-configured AODs in our method can be readily extended to two dimensions to address a two-dimensional ion crystal.
Cite
@article{arxiv.2306.01307,
title = {Low-crosstalk optical addressing system for atomic qubits based on multiple objectives and acousto-optic deflectors},
author = {Yi-Long Chen and Rui-Rui Li and Ran He and Shu-Qian Chen and Wen-Hao Qi and Jin-Ming Cui and Yun-Feng Huang and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:2306.01307},
year = {2025}
}