Influence of micro-joints formed between spheres in coupled-resonator optical waveguide.

Light propagation is simulated through coupled-resonator optical waveguides (CROWs) composed of seven transparent polystyrene microspheres, including micro-joints formed between the spheres. In nanojet-induced mode (NIM) light propagation, the micro-joints increased the optical coupling between microspheres drastically, and the light confinement by individual microspheres weakened as the micro-joint diameter increases. These results suggest that we can control NIM light propagation by changing the micro-joint diameter; this amounts to a nanojet throttle valve.