Zhang Haosen, Ping Wang Guo, Wu Kedi
Opt Lett. 2024 Aug 15;49(16):4654-4657. doi: 10.1364/OL.536497.
We present a novel, to the best of our knowledge, magneto-optical (MO) metasurface composed of a bismuth iron garnet (BIG) nanocube array, designed to achieve near-perfect absorption through quasi-bound states in the continuum (QBICs). This metasurface supports a stable QBIC mode induced by MO-induced permittivity terms that break the symmetry of the permittivity tensors, corresponding to a longitudinal electric dipole (ED) mode. By integrating graphene to introduce material loss, the absorption reaches 99.6% at a wavelength of 1512.3 nm with a Q factor of 9440, despite monolayer graphene's inherent absorption being only 2.3%. The inherent transverse ED background mode, with high reflection and low Q, helps decrease the radiative loss of the QBIC mode, allowing the structure to surpass the 50% absorption limit. This approach offers a simplified pathway for designing high-Q metasurface perfect absorbers, with potential applications in optical switches and modulators.
据我们所知，我们展示了一种新型的磁光（MO）超表面，它由铋铁石榴石（BIG）纳米立方体阵列组成，旨在通过连续体中的准束缚态（QBIC）实现近乎完美的吸收。这种超表面支持由磁光诱导的介电常数项诱导的稳定QBIC模式，这些项打破了介电常数张量的对称性，对应于纵向电偶极（ED）模式。通过集成石墨烯以引入材料损耗，尽管单层石墨烯的固有吸收率仅为2.3%，但在波长为1512.3 nm时吸收率仍达到99.6%，品质因数为9440。固有的横向ED背景模式具有高反射率和低品质因数，有助于降低QBIC模式的辐射损耗，使该结构能够超过50%的吸收极限。这种方法为设计高品质因数超表面完美吸收体提供了一条简化途径，在光开关和调制器方面具有潜在应用。
