Title: Metallic and All-Dielectric Metasurfaces Sustaining Displacement-Mediated Bound States in the Continuum Show Chinese title

Title: 金属和全介质超表面支持位移介导的连续谱中的束缚态

Abstract: 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, we numerically analyze and experimentally demonstrate an emerging class of BIC-driven metasurfaces, where the coupling to the far field is controlled by the displacement of individual resonators. In particular, we investigate both all-dielectric and metallic as well as positive and inverse displacement-mediated metasurfaces sustaining angular-robust quasi-BICs in the mid-infrared spectral region. We explore their behavior with changes in the incidence angle of illumination and experimentally show their superior performance compared to two conventional alternatives: silicon-based tilted ellipses and cylindrical nanoholes in gold. We anticipate our findings to open exciting perspectives for bio-sensing, conformal optical devices, and photonic devices using focused light. Show Chinese abstract

Abstract: 连续谱中的束缚态（BICs）是辐射波连续谱内的局域电磁模式。 由于它们没有辐射损耗且具有无限寿命，BICs 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，传统方法将 BICs 转换为具有高品质因数的泄漏共振或准 BICs 通常依赖于打破超表面的面内倒置对称性，并且通常导致对入射光角度高度依赖的共振，这使得它们不适合许多实际应用。 在这里，我们数值分析并实验演示了一类新兴的由 BIC 驱动的超表面，其中远场耦合由单个谐振器的位移控制。 特别是，我们研究了所有介质和金属以及正向和反向位移介导的超表面，在中红外光谱区域维持角度鲁棒的准 BICs。 我们探讨了它们在照明入射角变化时的行为，并实验展示了它们相对于两种传统替代方案（基于硅的倾斜椭圆和金中的圆柱形纳米孔）的优越性能。 我们预计我们的发现将为生物传感、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。