Liu Shuping, Fossati Alexandre, Serrano Diana, Tallaire Alexandre, Ferrier Alban, Goldner Philippe
Chimie ParisTech, PSL University, CNRS, Institut de Recherche de Chimie Paris, F-75005 Paris, France.
Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, 518055 Shenzhen, China.
ACS Nano. 2020 Aug 25;14(8):9953-9962. doi: 10.1021/acsnano.0c02971. Epub 2020 Jul 28.
Nanostructured systems that combine optical and spin transitions offer new functionalities for quantum technologies by providing efficient quantum light-matter interfaces. Rare-earth (RE) ion-doped nanoparticles are promising in this field as they show long-lived optical and spin quantum states. However, further development of their use in highly demanding applications, such as scalable single-ion-based quantum processors, requires controlling defects that currently limit coherence lifetimes. In this work, we show that a post-treatment process that includes multistep high-temperature annealing followed by high-power microwave oxygen plasma processing advantageously improves key properties for quantum technologies. We obtain single crystalline Eu:YO nanoparticles (NPs) of 100 nm diameter, presenting bulk-like inhomogeneous line widths (Γ) and population lifetimes (). Furthermore, a significant coherence lifetime () extension, up to a factor of 5, is successfully achieved by modifying the oxygen-related point defects in the NPs by the oxygen plasma treatment. These promising results confirm the potential of engineered RE NPs to integrate devices such as cavity-based single-photon sources, quantum memories, and processors. In addition, our strategy could be applied to a large variety of oxides to obtain outstanding crystalline quality NPs for a broad range of applications.
结合光学和自旋跃迁的纳米结构系统通过提供高效的量子光-物质界面，为量子技术带来了新功能。稀土（RE）离子掺杂的纳米粒子在该领域颇具前景，因为它们展现出长寿命的光学和自旋量子态。然而，要在诸如可扩展的单离子基量子处理器等要求苛刻的应用中进一步发展其用途，就需要控制目前限制相干寿命的缺陷。在这项工作中，我们表明一种后处理工艺，包括多步高温退火，随后进行高功率微波氧等离子体处理，有利地改善了量子技术的关键特性。我们获得了直径为100纳米的单晶Eu:YO纳米粒子（NPs），呈现出类似体材料的非均匀线宽（Γ）和布居寿命（）。此外，通过氧等离子体处理改变纳米粒子中与氧相关的点缺陷，成功实现了相干寿命（）延长至高达5倍。这些有前景的结果证实了工程化稀土纳米粒子在集成诸如基于腔的单光子源、量子存储器和处理器等器件方面的潜力。此外，我们的策略可应用于多种氧化物，以获得用于广泛应用的具有出色晶体质量的纳米粒子。
