Title: Design of Ultrathin Faraday Rotators based on All-dielectric Magneto-optical Metasurfaces at the Telecommunication Band Show Chinese title

Title: 基于全介质磁光超表面的通信波段超薄法拉第旋转器的设计

Abstract: Magneto-optical (MO) interactions offer a direct route to nonreciprocal optical devices but are intrinsically weak in the optical domain, posing a major challenge in downsizing MO functional devices. In this study, we present a design strategy for ultra-thin MO Faraday rotators based on all-dielectric metasurfaces supporting high-quality factor quasi-bound states in the continuum (QBIC) modes. Light trapping in QBIC modes induced by band folding significantly enhances MO interactions in a controllable manner, enabling a technologically relevant 45$^\circ$ Faraday rotation with a MO metasurface that is only a few hundred nanometers thick. The design also incorporates electromagnetically induced transparency via spectrally overlapping resonant modes to achieve high light transmittance reaching 80%. This approach not only enables compact yet practical MO Faraday rotator but also holds promises for advancing free-space magnetic sensors and MO modulators. Show Chinese abstract

Abstract: 磁光（MO）相互作用为非互易光学器件提供了一条直接路径，但在光域中本质上很弱，这在缩小MO功能器件方面构成了重大挑战。 在本研究中，我们提出了一种基于全介质超表面的超薄MO法拉第旋转器的设计策略，该超表面支持高品质因数的准连续态中的束缚态（QBIC）模式。 由带折叠引起的QBIC模式中的光捕获显著地以可控方式增强了MO相互作用，使得仅几百分之一纳米厚的MO超表面实现了45$^\circ$的法拉第旋转。 该设计还通过光谱重叠的共振模式实现了电磁诱导透明，以实现高达80%的高光透过率。 这种方法不仅实现了紧凑而实用的MO法拉第旋转器，而且对于推进自由空间磁传感器和MO调制器具有前景。