High-lying Rydberg states of Mott-Wannier excitons are receiving considerable interest due to the possibility of adding long-range interactions to the physics of excitons. Here, we study Rydberg excitation in bulk synthetic cuprous oxide grown by the optical float zone technique and compare the result with natural samples. X-ray characterization confirms both materials are mostly single crystal, and midinfrared transmission spectroscopy revealed little difference between synthetic and natural material. The synthetic samples show principal quantum numbers up to $n=10$, exhibit additional absorption lines, plus enhanced spatial broadening and spatial inhomogeneity. Room temperature and cryogenic photoluminescence measurements reveal a significant quantity of copper vacancies in the synthetic material. These measurements provide a route towards achieving high-$n$ excitons in synthetic crystals, opening a route to scalable quantum devices.

中文翻译：

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合成氧化亚铜Cu2O中的里德堡激子

由于可能将长程相互作用添加到激子物理学中，莫特-万尼尔激子的高位里德堡态受到了相当大的关注。在这里，我们研究了通过光学浮区技术生长的大块合成氧化亚铜中的里德堡激发，并将结果与​​天然样品进行了比较。X 射线表征证实两种材料大多是单晶，中红外透射光谱显示合成材料和天然材料之间几乎没有区别。合成样品显示主量子数高达$n=10$，表现出额外的吸收线，以及增强的空间展宽和空间不均匀性。室温和低温光致发光测量显示合成材料中存在大量铜空位。这些测量提供了实现高$n$ 合成晶体中的激子，为可扩展的量子设备开辟了道路。