Magnetization reversal by circularly polarized light

Generally called all-optical switching, this technique refers to a method of reversing magnetization in a ferromagnet simply by circularly polarized light (see Fig. 1.10), where the magnetization direction is controlled by the light helicity. In particular, the direction of the angular momentum of the photons would set the magnetization direction. In fact, this process could be seen as similar to magnetization reversal by spin injection. The only difference is that now, the angular momentum is supplied by the circularly polarized photons instead of the polarized electrons.