Xu Guizhen, Xue Zhanqiang, Fan Junxing, Lu Dan, Xing Hongyang, Shum Perry Ping, Zhou Ye, Cong Longqing
State Key Laboratory of Optical Fiber and Cable Manufacture Technology, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Guangdong Key Laboratory of Integrated Optoelectronics Intellisense, Southern University of Science and Technology, Shenzhen, 518055, China.
Adv Mater. 2024 Oct;36(40):e2406526. doi: 10.1002/adma.202406526. Epub 2024 Aug 17.
Terahertz absorbers are crucial to the cutting-edge techniques in the next-generation wireless communications, imaging, sensing, and radar stealth, as they fundamentally determine the performance of detectors and cloaking capabilities. It has long been a pressing task to find absorbers with customizable performance that can adapt to various environments with low cost and great flexibility. Here, perfect absorption empowered by bound states in the continuum (BICs) is demonstrated, allowing for the tailoring of absorption coefficient, bandwidth, and field of view. The one-port absorbers are interpreted using temporal coupled-mode theory highlighting the dominant role of BICs in the far-field radiation properties. Through a thorough investigation of BICs from the perspective of lattice symmetry, the radiation features of three BIC modes are unraveled using both multipolar and topological analysis. The versatile radiation capabilities of BICs provide ample freedom to meet specific requirements of absorbers, including tunable bandwidth, stable performance in a large field of view, and multiband absorption using a thin and flexible film without extreme geometric demands. These findings offer a systematic approach to developing optoelectronic devices and demonstrate the significant potential of BICs for optical and photonic applications, which will stimulate further studies on terahertz photonics and metasurfaces.
太赫兹吸收器对于下一代无线通信、成像、传感和雷达隐身等前沿技术至关重要，因为它们从根本上决定了探测器的性能和隐身能力。长期以来，寻找具有可定制性能、能够以低成本和高灵活性适应各种环境的吸收器一直是一项紧迫的任务。在此，展示了由连续统中的束缚态（BIC）实现的完美吸收，从而能够对吸收系数、带宽和视场进行定制。使用时间耦合模理论对单端口吸收器进行了解释，突出了BIC在远场辐射特性中的主导作用。通过从晶格对称性的角度对BIC进行深入研究，利用多极和拓扑分析揭示了三种BIC模式的辐射特征。BIC的多功能辐射能力为满足吸收器的特定要求提供了充分的自由度，包括可调带宽、在大视场中的稳定性能以及使用薄且灵活的薄膜实现多波段吸收而无需极端的几何要求。这些发现为开发光电器件提供了一种系统方法，并证明了BIC在光学和光子应用中的巨大潜力，这将激发对太赫兹光子学和超表面的进一步研究。
