Magnetic Field out of Light

While the electronic industry has successfully entered the nanoworld following Moore’s law, the speed of manipulating and storing data lags behind, creating the so-called ultrafast technology gap. Processors already have a clock speed of a few gigahertz, while the storage on a magnetic hard disk requires a few nanoseconds. This bottleneck can also be found in magnetic random access memory devices. 

The use of ultrafast pulses of light has demonstrated effectiveness in manipulating magnetic orders on very short time scales. However, the physical processes involved are still poorly understood, and such a control reaches the micrometer scale at best, effectively preventing their use for high-density data storage.

This research project aims to develop an entirely new approach to manipulating magnetic domains based on the engineering of plasmonic nanodevices. For that, these devices optically generate ultrashort, intense, and reversible pulses of magnetic field at the nanoscale, a challenge that no other technique can achieve so far. 

For that purpose, we engineer innovative plasmonic nanostructures inversely-designed to tailor light-matter interactions at the nanoscale. Under the right illumination conditions, the electromagnetic fields generated by the nanostructure set the electrons in a metal (such as in a coil) in pseudo-continuous drift motion, in turn yielding the creation of a strong stationary magnetic field.

By specifically creating and manipulating ultrafast, strong, confined and reversible pulses of magnetic field in an all-optical fashion, we will enable the manipulation of magnetic domains at the nanoscale and over very short timescales (a few tens of femtoseconds), opening the way to applications in ultrafast data storage and data processing. As well, it will also open up entirely new horizons in technological and research areas as diverse as electron spin manipulation, spin precession, spin current and spin waves, in improving the capability to control the acceleration of charged particles in laser-plasma interaction or nano-MRI studies, amongst others.