Optical beam shaping induced reconfigurable magnetic domains

Abstract Ultrafast all-optical switching (AOS) in ferromagnets has emerged as a promising route toward dense and energy-efficient magnetic memory. However, its implementation has typically been limited by material-specific polarization requirements or by the need for auxiliary exchange coupling and compositional tuning. Here, we demonstrate that deterministic control of AOS can instead be achieved purely through optical engineering. By tailoring the polarization distribution and focusing of the excitation light, we shift the selectivity from intrinsic material properties to external optical beam shaping. In stand-alone [Pt/Co] N multilayers, this enables direct control over local heating and optical torques, allowing the system to be driven either into helicity-dependent, multishot domain-wall propagation or into helicity-independent magnetization reversal, without material modification or external bias fields. Our results establish optical beam design as a universal control knob for magnetization dynamics in ferromagnetic systems, defining a scalable pathway for integrating ultrafast spintronic functionality with on-chip photonics.