Fabrication robustness in BIC metasurfaces
Fabrication robustness in BIC metasurfaces
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DOI：
10.1515/nanoph-2021-0391
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发表时间：
2021-12-01
期刊：
影响因子：
7.5
通讯作者：
Tittl, Andreas
中科院分区：
文献类型：
--
作者：
Kuehne, Julius;Wang, Juan;Tittl, Andreas
全介质超颖表面支持光子束缚态的连续（BIC）是一个令人兴奋的工具包，实现超窄线宽的共振。然而，从理论到实验实现的过渡会显著降低基于BIC的纳米光子系统的光学性能，严重限制其应用潜力。在这里，我们介绍了一个组合的numerical/实验方法来预测如何不可避免的公差，如随机几何变化的nanofabrics影响不同的BIC超表面设计的性能。我们比较了几个已建立的全介质BIC单元格的几何形状与打破面内反转对称，包括倾斜的椭圆，不对称的双杆，和分裂环。值得注意的是，即使对于低的制造引起的几何变化，BIC共振振幅和其品质因数（Q因数）都显著降低。我们发现，全介质椭圆保持最高的Q-因子在整个几何变化范围内，而杆和分裂环的几何形状下降得更快。实验证实了相同的行为，其中几何变化值来自扫描电子显微镜（SEM）图像集的自动处理。我们的方法提供了至关重要的见解BIC metasurfaces的性能退化时，从模拟到制造的样品，并将使强大的，高Q值，易于制造的纳米光子平台的应用范围从生物分子传感到高次谐波产生的发展。
All-dielectric metasurfaces supporting photonic bound states in the continuum (BICs) are an exciting toolkit for achieving resonances with ultranarrow linewidths. However, the transition from theory to experimental real-ization can significantly reduce the optical performance of BIC-based nanophotonic systems, severely limiting their application potential. Here, we introduce a combined nu-merical/experimental methodology for predicting how unavoidable tolerances in nanofabrication such as random geometrical variations affect the performance of different BIC metasurface designs. We compare several established all-dielectric BIC unit cell geometries with broken in-plane inversion symmetry including tilted ellipses, asymmetric double rods, and split rings. Significantly, even for low fabrication-induced geometrical changes, both the BIC resonance amplitude and its quality factor (Q-factor) are significantly reduced. We find that the all-dielectric ellip-ses maintain the highest Q-factors throughout the geometrical variation range, whereas the rod and split ring geometries fall off more quickly. The same behavior is confirmed experimentally, where geometrical variation values are derived from automated processing of sets of scanning electron microscopy (SEM) images. Our meth-odology provides crucial insights into the performance degradation of BIC metasurfaces when moving from simulations to fabricated samples and will enable the development of robust, high-Q, and easy to manufacture nanophotonic platforms for applications ranging from biomolecular sensing to higher harmonic generation.