Zhang Xiaoqiang, Jiang Yunqing, Li Qiuyue, Xu Yong, Zhan Qiwen, Zhao Weishneg
Opt Express. 2024 Oct 21;32(22):38720-38729. doi: 10.1364/OE.538811.
The magneto-optical Kerr effect (MOKE), as one of the magneto-optical effects, exhibits polarization change upon reflection that can be used to explore the internal information of magnetic materials with broad applications in modern information technology. However, typically, MOKE is quite weak due to the lower magneto-optical interaction. To tremendously enhance the MOKE, quasi-bound states in the continuum in a one-dimensional Ce- doped YFeO (CeYIG) film photonic crystal slabs (PCS) are proposed to improve the magneto-optical interaction in this work. A giant enhancement in the rotation angle and ellipticity of the longitudinal MOKE, which is about 93.4 and 136.8 times stronger than a pure uniform CeYIG, can be realized. Almost circularly polarized reflected beams with different chiralities are obtained with the CeYIG film. By tuning the geometric parameters of the PCS and the applied external magnetic field, dynamic control of polarization states of the reflected beams with different wavelengths can be realized. This magneto-optical metasurface provides a convenient way for the implementation of magneto-optical devices such as information memory devices, sensors, polarizers, and chiral devices.
磁光克尔效应（MOKE）作为磁光效应之一，在反射时会表现出偏振变化，可用于探究磁性材料的内部信息，在现代信息技术中有广泛应用。然而，通常情况下，由于磁光相互作用较弱，MOKE相当微弱。为了极大地增强MOKE，本文提出在一维掺铈钇铁石榴石（CeYIG）薄膜光子晶体平板（PCS）中利用连续态中的准束缚态来改善磁光相互作用。纵向MOKE的旋转角和椭圆率可实现巨大增强，比纯均匀CeYIG强约93.4倍和136.8倍。利用CeYIG薄膜可获得具有不同手性的近圆偏振反射光束。通过调整PCS的几何参数和施加的外部磁场，可实现对不同波长反射光束偏振态的动态控制。这种磁光超表面为实现诸如信息存储器件、传感器、偏振器和手性器件等磁光器件提供了一种便捷方式。
