Metallic and All-Dielectric Metasurfaces Sustaining Displacement-Mediated Bound States in the Continuum
Metallic and All-Dielectric Metasurfaces Sustaining Displacement-Mediated Bound States in the Continuum
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DOI：
10.1002/adom.202301269
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发表时间：
2023-09-01
影响因子：
9
通讯作者：
Tittl，Andreas
中科院分区：
文献类型：
--
作者：
Berger，Luca M.;Barkey，Martin;Tittl，Andreas
连续体束缚态 (BIC) 是辐射波连续谱内的局域电磁模式。由于 BIC 具有无限的寿命且没有辐射损失，因此正在推动激光、非线性光学过程和传感领域的研究方向。然而，将 BIC 转换为具有高质量因子的漏谐振或准 BIC 的传统方法通常依赖于打破超表面的面内反演对称性，并且通常会导致强烈依赖于入射光角度的谐振，使得它们不适合许多实际应用。在这里，对一类新兴的 BIC 驱动超表面进行了数值分析和实验演示，其中与远场的耦合由各个谐振器的位移控制。特别是，在中红外光谱区域研究了支持角鲁棒准 BIC 的全电介质和金属以及正位移介导的超表面和反位移介导的超表面。研究人员对它们随入射角变化的光学行为进行了研究，并通过实验证明了它们与两种传统替代品（硅基倾斜椭圆和金圆柱形纳米孔）相比的优越性能。这些发现预计将为生物传感、共形光学器件和使用聚焦光的光子器件开辟令人兴奋的前景。
Bound states in the continuum (BICs) are localized electromagnetic modes within the continuous spectrum of radiating waves. Due to their infinite lifetimes without radiation losses, BICs are driving research directions in lasing, non‐linear optical processes, and sensing. However, conventional methods for converting BICs into leaky resonances, or quasi‐BICs, with high‐quality factors typically rely on breaking the in‐plane inversion symmetry of the metasurface and often result in resonances that are strongly dependent on the angle of the incident light, making them unsuitable for many practical applications. Here, an emerging class of BIC‐driven metasurfaces is numerically analyzed and experimentally demonstrated, where the coupling to the far field is controlled by the displacement of individual resonators. In particular, both all‐dielectric and metallic as well as positive and inverse displacement‐mediated metasurfaces sustaining angular‐robust quasi‐BICs are investigated in the mid‐infrared spectral region. Their optical behavior with regard to changes in the angle of incidence is investigated and experimentally shows their superior performance compared to two conventional alternatives: silicon‐based tilted ellipses and cylindrical nanoholes in gold. These findings are anticipated to open exciting perspectives for bio‐sensing, conformal optical devices, and photonic devices using focused light.