Ultrafast all-optical magnetization switching enhanced by a photonic crystal

All-optical magnetization switching driven by femtosecond lasers offers a promising solution for data storage. To address power consumption, optical enhancement methods based on the two-temperature model can reduce energy requirements for magnetization reversal. To achieve this, we design a phase-matched optical resonant cavity formed between photonic crystals and multilayer ferrimagnetic films. This cavity with band filtering properties enables dual detection through transmission and reflection, similar to the all-optical switching films, facilitating high-density storage device integration. Finite element simulations are employed to adjust key photonic crystal parameters, ensuring theoretically optimal location of the pump laser. Experimental results demonstrate that over 87% of the 800-nm-pump laser is absorbed. A twofold pump laser fluence reductions for magnetization reversal are validated through static magneto-optical Kerr effect microscopy and time-resolved magneto-optical Kerr effect measurements. Our results provide substantial advances toward low-energy consumption and high-density compatibility characteristics for the next-generation ultrafast magneto-optical storage devices.