Meta-Magnetic All-Optical Helicity Dependent Switching of Ferromagnetic Thin Films

To address the ever-increasing need for higher speed and density of information storage, recent developments in ultrafast optical switching have focused on deterministic control of magnetic properties of materials using femtosecond circularly polarized optical pulses. However, a monolithic high-speed optical helicity-dependent switching at room temperature has remained elusive. In recent years, ultra-thin flat optical structures, known as metasurfaces, have been developed that offer a versatile way to manipulate electromagnetic fields using subwavelength spatial resolution. Here, a monolithic multilayer nanostructure capable of achieving optical helicity-dependent switching in arbitrary geometries using femtosecond meta-circularly polarized optical pulses is theoretically described and experimentally demonstrated at room temperature. The proposed monolithic meta-magnetic platform provides a practical route to reform the current data memory, storage, and information processing technologies in integrated opto-magnetic systems, holding great promise for cutting-edge applications in information, spintronics, sensing, and memory storage devices. The proposed platform can conveniently generate a monolithic high-speed optical helicity-dependent switching at room temperature, and more importantly, it carries full reconfigurability to control magnetic domains, which is highly desirable but far from being realized based upon the prior research results in the field.image