Researchers have found a way to enhance the force of light on matter. Most of the time the momentum of light and the associated forces are too small to notice, but at the nanoscale the effect can be quite large, and researchers have used these forces to dynamically manipulate optical waveguides at the nanoscale. Optical forces decay significantly, however, as the distance between the waveguides increases and become too small for all-optical device actuation at larger separations. The new method amplifies the optical forces and thus extends them to larger separations between the waveguides by using a novel way to alter the perceived distance between them. This is done with thin layers of engineered structures known as metamaterials, which can manipulate light in ways not seen in conventional materials, extending its influence to greater distances from the surfaces of the waveguide. This work paves the way for the production of optical forces with unprecedented amplitude and eventually the design of mechanical devices activated entirely by light.
Enhancing Optical Gradient Forces with Metamaterials