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Ultrafast magnetization reversal with laser pulses

Traditionally, magnetic fields are used to flip the magnetization in materials, encoding digital information. But Peeters investigated a promising alternative: all-optical switching (AOS), where laser pulses are used to reverse magnetization. His work confirms that bilayer structures, which are easier to engineer than ferrimagnetic alloys, can switch just as fast, making them attractive for future applications.

He also showed that relatively small external magnetic fields can influence the switching process within just tens of picoseconds, primarily through precessional switching, a dynamic effect where the magnetization spirals toward its new direction.

Controlling magnetization with light helicity

Another form of AOS involves circularly polarized light, where the 鈥渢wist鈥� of the light determines the final magnetic state. This helicity-dependent switching offers precise control but typically requires multiple pulses. Peeters studied how factors like laser fluence, repetition rate, and material thickness affect this process, and found a link between the size of magnetic domains and the presence of switching鈥攐ffering new insights into optimizing this technique.

Detecting spin waves with ultrafast optics

In the final part of his thesis, Peeters turned to spin waves鈥攔ipples of magnetization that travel through materials and could be used in wave-based computing. These waves offer advantages such as low power consumption and high-frequency operation, making them promising candidates for future logic devices.

Peeters developed a novel method to detect spin waves with very short wavelengths, using ultrafast laser pulses and a metallic grating. This technique allows for spatially resolved, wavelength-selective detection, and could help miniaturize future magnonic technologies.

Toward next-generation data and logic devices

Peeters鈥� work provides new insights into ultrafast magnetization dynamics and spin wave detection. These findings bring us closer to developing next-generation logic and storage technologies that are faster, smaller, and more energy-efficient.