Development of low-loss photonic components in the ultraviolet (UV) band will open new prospects for classical and quantum optics. Compared with other integrated platforms, aluminum nitride (AlN) is particularly attractive as it features an enormous bandgap of $\sim 6.2\mathrm{eV}$ and intrinsic ${\chi }^{(2)}$ and ${\chi }^{(3)}$ susceptibilities. In this work, we demonstrate a record quality factor of $2.1\times {10}^5$ (optical loss $\sim 8\mathrm{dB}/\mathrm{cm}$) at 390 nm based on single-crystalline AlN microrings. The low-loss AlN waveguide represents a significant milestone toward UV photonic integrated circuits as it features full compatibility for future incorporation of AlGaN-based UV emitters and receivers. On-chip UV spectroscopy, nonlinear optics, and quantum information processing can also be envisioned.

中文翻译：

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基于单晶AlN平台的超高Q UV微环谐振器

紫外（UV）波段低损耗光子组件的开发将为经典光学和量子光学打开新的前景。与其他集成平台相比，氮化铝（AlN）特别具有吸引力，因为它具有巨大的带隙。$〜6.2\mathrm{电子伏特}$ 和内在的 ${\chi }^{（\mathrm{2个}）}$ 和 ${\chi }^{（3）}$敏感性。在这项工作中，我们展示了创纪录的品质因数$2.1\times {10}^5$ （光损耗 $〜8\mathrm{D\; b}/\mathrm{厘米}$）在390 nm下基于单晶AlN微环。低损耗的AlN波导代表了迈向UV光子集成电路的重要里程碑，因为它具有与将来基于AlGaN的UV发射器和接收器的完全兼容性。还可设想片上UV光谱，非线性光学和量子信息处理。