Coherent control of photomagnetic back-switching by double-pump laser pulses

The ultrafast all-optical control of magnetization without relying on heat is promising for magnetic recording technology. While the magnetization switching between two stable bit states does not require control over light polarization, photomagnetic toggling of magnetization (equivalent to the XOR logic operation) can be achieved. This study probes the efficiency of a back-switching scenario between two stable bit states, using a pair of femtosecond laser pulses with either the same or orthogonal orientations of linear polarization. Such a nonthermal toggle regime not only can provide recording at rates up to 50 GHz, but also can perform basic logic operations.