Conventionally, tuning magneto-optical Kerr rotation via the excitation of surface plasmons (SPs) usually results in extremely low light energy at the Kerr null point position in the optical spectrum. Realizing independent control of the magneto-optical effect is considered as an effective solution. The decoupling between the Kerr effect and optical response is achieved in our constructed Ag/Co composite nanogratings, and the Kerr rotation used as the refractive index sensing signal can be obtained without SP excitation. The refractive index sensing performance is improved by reducing electron collision frequency in Ag/Co nanogratings and the figure of merit reaches 96/RIU, far exceeding that of Co nanogratings.

通常，通过表面等离子体激元 (SP) 的激发来调整磁光克尔旋转通常会导致光谱中克尔零点位置处的光能极低。实现磁光效应的独立控制被认为是一种有效的解决方案。在我们构建的 Ag/Co 复合纳米光栅中实现了克尔效应和光学响应之间的解耦，并且可以在没有 SP 激发的情况下获得用作折射率传感信号的克尔旋转。通过降低Ag/Co纳米光栅中的电子碰撞频率来提高折射率传感性能，品质因数达到96/RIU，远远超过Co纳米光栅。