Abstract
High-performance, miniaturized magneto-optical (MO) devices play a critical role in near-infrared (NIR) opto-electronic systems for energy-related and precision optical applications. However, conventional MO materials generally exhibit weak Faraday rotation and insufficient transmittance in the NIR band. We proposed a chiral magneto-plasmonic heterostructure based on bismuth-substituted yttrium iron garnet, in which a gold nanoparticle array with symmetry-breaking characteristics was fabricated on the surface. The results indicate that localized surface plasmon resonances can be effectively excited, and a synergistic enhancement of Faraday rotation and optical transmission in the NIR band can be achieved. We systematically investigate the effects of particle type and structural parameters on device performance and analyzes the underlying physical mechanisms. The results show that the proposed chiral heterostructure enables a more favorable balance between Faraday rotation and transmittance in the NIR band, enhancing the efficiency of MO devices and expanding their application range. Its overall performance metrics exceed those of conventional periodic structures. We provide a feasible structural approach for achieving high-performance MO responses in the NIR band and offers a theoretical and design basis for the development of compact non-reciprocal MO devices.