Here are some of the previous statements that can be found in the literature which would indicate that the all-optical switching of magnetization (due to the angular momentum of the photons) should be fundamentally impossible:

• No matter how short and strong the magnetic-field pulse, magnetic recording cannot be made ever faster than picosecond.[1-5]
• “The amount of the photons involved in the experiments is far not enough to contribute a significant angular momentum.”[6]
• “In metals, electron-electron scattering appears to make coherent manipulation of magnetization difficult if not impossible […] Therefore, one cannot expect to induce coherent electron spin dynamics in metals with laser pulses of 30 fs duration.” [7]