Directing nanoparticles with polarized light

Francisco Rodríguez-Fortuño and Anatoly Zayats from the Department of Physics at King’s College London, in collaboration with scientists in Spain and the USA, have shown that it is theoretically possible to move a nanoparticle laterally using a beam of circularly polarised light, provided it is close to any surface.
 
Circularly polarised light beams consist of photons that all have the same spin (one of the fundamental properties of photons). It was already known that this kind of light causes nanoparticles to rotate and now, in a paper published in Nature Communications, the authors demonstrate that in addition to this rotation the particle will also experience a lateral net force causing it to move. They also suggest that, by switching the spin of the photons, it is possible to change the direction of the force. This lateral force is a consequence of a phenomenon known as “spin-orbit interaction of light”. This force could lead to new nanotechnological and medical applications for the optical manipulation of particles and atoms, driven by the polarization of light.

In addition, Francisco Rodríguez-Fortuño and Anatoly Zayats recently published a review article in Nature Photonics, in collaboration with K. Bliokh and F. Nori from Japan, as part of a special issue focussing on the topic.