In a study that could lead to advances in the emerging fields of optical computing and nanomaterials, researchers at Missouri University of Science and Technology report that a new class of nanoscale slot waveguides pack 100 to 1,000 times more transverse optical force than conventional silicon slot waveguides.
In a recent study, Gao and Yang describe the unusual optical and mechanical properties of nanometer-scale metal-dielectric structures called metamaterials. The researchers created computer simulations of nanometer-scale models of metamaterial slot waveguides, which are structures designed to channel beams of light from one area to another. Waveguides function like tiny filaments or the wires of an integrated circuit, but on a much smaller scale.
For their study, the Missouri S&T researchers simulated slot waveguides made of layered structures of a metal (in this case, silver) and a dielectric material (germanium), arranged like the alternating bread and meat in a club sandwich. A nanometer - visible only with the aid of a high-power electron microscope - is one billionth of a meter, and some nanomaterials are only a few atoms in size.
Gao and Yang simulated what would happen with modeled identical waveguides - each 40 nanometers wide and 30 nanometers tall - that were stacked with a tiny air gap between them. They then measured the transverse optical force between the two waveguides. Optical force refers to the way beams of light can be made to attract or repel each other, as magnets do. In their experiments on the simulated metamaterials, the Missouri S&T researchers found that "the transverse optical forces in slot waveguides of hyperbolic metamaterials can be over two orders of magnitude stronger than that in conventional dielectric slot waveguides.