Highlighted Articles from Optica Publishing Group Journals
Spotlight Summary by Vassilios Kapaklis
Light-induced thermomagnetic recording of thin-film magnet CoFeB on silicon waveguide for on-chip magneto-optical memory
Bringing up the term “speed of light” often makes us think of velocities, but there is more to it, as light can induce ultrafast changes to properties of condensed matter. A prominent example is the interaction of light with the magnetization in materials, where ultrafast and energy efficient switching may be achieved. While there are ways to produce power dense, ultrafast pulses of light using lasers, a caveat still lies in our ability to efficiently couple that light to magnetic materials and structures. This would allow for further reduction of the energy requirements and timescales for switching in magnetic structures, relevant for information storage. Toshiya Murai et al. present a way to couple that light to magnetic microstructures, utilizing optical waveguides having dimensions on the same length-scale. They successfully demonstrate switching events under weak bias magnetic fields, for continuous light illumination, but also for nanosecond light pulses. The introduction of these waveguides removes the requirement of bulky optics and light sources, facilitating monolithic fabrication as in modern microelectronics. In the near future it might be possible to address all the individual microstructures with miniaturized photonic integrated circuits, realizing non-volatile memories fully addressed by light.