Lu Xiyuan, Zhou Feng, Sun Yi, Chanana Ashish, Wang Mingkang, McClung Andrew, Aksyuk Vladimir A, Davanco Marcelo, Srinivasan Kartik
Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Joint Quantum Institute, NIST/University of Maryland, College Park, MD 20742, USA.
Nanophotonics. 2023 Jan 10;12(3):521-529. doi: 10.1515/nanoph-2022-0622. eCollection 2023 Feb.
Micro-/nanocavities that combine high quality factor () and small mode volume () have been used to enhance light-matter interactions for cavity quantum electrodynamics (cQED). Whispering gallery mode (WGM) geometries such as microdisks and microrings support high- and are design- and fabrication-friendly, but is often limited to tens of cubic wavelengths to avoid WGM radiation. The stronger modal confinement provided by either one-dimensional or two-dimensional photonic crystal defect geometries can yield sub-cubic-wavelength , yet the requirements on precise design and dimensional control are typically much more stringent to ensure high-. Given their complementary features, there has been sustained interest in geometries that combine the advantages of WGM and photonic crystal cavities. Recently, a "microgear" photonic crystal ring (MPhCR) has shown promise in enabling additional defect localization ( 10× reduction of ) of a WGM, while maintaining high- and other WGM characteristics in ease of coupling and design. However, the unit cell geometry used is unlike traditional PhC cavities, and etched surfaces may be too close to embedded quantum nodes (quantum dots, atomic defect spins, etc.) for cQED applications. Here, we report two novel PhCR designs with "rod" and "slit" unit cells, whose geometries are more traditional and suitable for solid-state cQED. Both rod and slit PhCRs have high- with WGM coupling properties preserved. A further ≈10× reduction of by defect localization is observed in rod PhCRs. Moreover, both fundamental and 2nd-order PhC modes co-exist in slit PhCRs with high s and good coupling. Our work showcases that high-/ PhCRs are in general straightforward to design and fabricate and are a promising platform to explore for cQED.
结合高品质因数（ ）和小模式体积（ ）的微/纳米腔已被用于增强腔量子电动力学（cQED）中的光与物质相互作用。微盘和微环等回音壁模式（WGM）几何结构支持高 且对设计和制造友好，但 通常限于几十立方波长以避免WGM辐射。一维或二维光子晶体缺陷几何结构提供的更强模式限制可产生亚立方波长的 ，然而，为确保高 ，对精确设计和尺寸控制的要求通常要严格得多。鉴于它们的互补特性，人们一直对结合WGM和光子晶体腔优势的几何结构持续感兴趣。最近，一种“微齿轮”光子晶体环（MPhCR）已显示出有望实现WGM的额外缺陷定位（ 降低10倍），同时在易于耦合和设计方面保持高 和其他WGM特性。然而，所使用的晶胞几何结构不同于传统的光子晶体腔，并且蚀刻表面对于cQED应用可能离嵌入式量子节点（量子点、原子缺陷自旋等）太近。在这里，我们报告了两种具有“杆”和“狭缝”晶胞的新型光子晶体环设计，其几何结构更传统且适用于固态cQED。杆状和狭缝状光子晶体环都具有高 且保留了WGM耦合特性。在杆状光子晶体环中观察到通过缺陷定位 进一步降低了约10倍。此外，在狭缝状光子晶体环中，基模和二阶光子晶体模式以高 且良好耦合的方式共存。我们的工作表明，高 / 的光子晶体环总体上设计和制造都很简单，是探索cQED的一个有前途的平台。
