Sortino Luca, Gale Angus, Kühner Lucca, Li Chi, Biechteler Jonas, Wendisch Fedja J, Kianinia Mehran, Ren Haoran, Toth Milos, Maier Stefan A, Aharonovich Igor, Tittl Andreas
Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany.
School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
Nat Commun. 2024 Mar 5;15(1):2008. doi: 10.1038/s41467-024-46272-1.
Van der Waals (vdW) materials, including hexagonal boron nitride (hBN), are layered crystalline solids with appealing properties for investigating light-matter interactions at the nanoscale. hBN has emerged as a versatile building block for nanophotonic structures, and the recent identification of native optically addressable spin defects has opened up exciting possibilities in quantum technologies. However, these defects exhibit relatively low quantum efficiencies and a broad emission spectrum, limiting potential applications. Optical metasurfaces present a novel approach to boost light emission efficiency, offering remarkable control over light-matter coupling at the sub-wavelength regime. Here, we propose and realise a monolithic scalable integration between intrinsic spin defects in hBN metasurfaces and high quality (Q) factor resonances, exceeding 10, leveraging quasi-bound states in the continuum (qBICs). Coupling between defect ensembles and qBIC resonances delivers a 25-fold increase in photoluminescence intensity, accompanied by spectral narrowing to below 4 nm linewidth and increased narrowband spin-readout efficiency. Our findings demonstrate a new class of metasurfaces for spin-defect-based technologies and pave the way towards vdW-based nanophotonic devices with enhanced efficiency and sensitivity for quantum applications in imaging, sensing, and light emission.
包括六方氮化硼（hBN）在内的范德华（vdW）材料是层状晶体固体，在研究纳米尺度的光与物质相互作用方面具有吸引人的特性。hBN已成为纳米光子结构的通用构建块，最近发现的天然光学可寻址自旋缺陷为量子技术开辟了令人兴奋的可能性。然而，这些缺陷表现出相对较低的量子效率和较宽的发射光谱，限制了潜在应用。光学超表面提出了一种提高光发射效率的新方法，在亚波长范围内对光与物质的耦合提供了显著的控制。在这里，我们提出并实现了hBN超表面中的本征自旋缺陷与高质量（Q）因子共振（超过10）之间的单片可扩展集成，利用连续统中的准束缚态（qBICs）。缺陷集合与qBIC共振之间的耦合使光致发光强度提高了25倍，同时光谱线宽缩小到4nm以下，并提高了窄带自旋读出效率。我们的研究结果展示了一类用于基于自旋缺陷技术的新型超表面，并为基于vdW的纳米光子器件铺平了道路，这些器件在成像、传感和光发射的量子应用中具有更高的效率和灵敏度。
