The quantum confinement of Rydberg excitons is an important step towards exploiting their large nonlinearities for quantum applications. We observe Rydberg excitons in natural nanoparticles of ${\mathrm{Cu}}_2\mathrm{O}$. We resolve up to the principal quantum number $n=12$ in a bulk ${\mathrm{Cu}}_2\mathrm{O}$ crystal and up to $n=6$ in nanoparticles extracted from the same crystal. The exciton transitions in nanoparticles are broadened and their oscillator strengths decrease as $\propto n^{-4}$ compared to those in the bulk (decreasing as $\propto n^{-3}$). We explain our results by including the effect of quantum confinement of exciton states in the nanoparticles. Our results provide an understanding of the physics of ${\mathrm{Cu}}_2\mathrm{O}$ Rydberg excitons in confined dimensions.

中文翻译：

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Cu2Onanoparticles中的量子限制里德堡激子

里德堡激子的量子限制是将其大非线性用于量子应用的重要一步。我们在天然纳米粒子中观察到里德堡激子${铜}_2\mathrm{哦}$. 我们解析到主量子数$n=12$ 大量 ${铜}_2\mathrm{哦}$ 水晶和高达 $n=6$在从同一晶体中提取的纳米颗粒中。纳米粒子中的激子跃迁变宽，它们的振子强度随着$\propto n^{-4}$ 与大部分相比（减少为 $\propto n^{-3}$）。我们通过包括纳米粒子中激子态的量子限制效应来解释我们的结果。我们的结果提供了对物理学的理解${铜}_2\mathrm{哦}$ 受限维度中的里德堡激子。