Ultra-short plasmonic splitters and waveguide cross-over based on coupled surface plasmon slot waveguides.

Composite metal-dielectric-metal (MDM) surface plasmon polariton (SPP) structures are first proposed to realize the ultra-short optical splitters with simplified designs. The operation mechanism is based on the contra-directional coupling achieved in composite plasmonic slot waveguides. In certain cases, the switching function can also be realized. It is further shown that based on the same physical mechanism multi-dielectric-core composite MDM structures could serve as a novel plasmonic waveguide crossover component with low cross talk and high throughput.

Fabrication of centimeter-sized single-domain two-dimensional colloidal crystals in a wedge-shaped cell under capillary forces.

Self-assembly of colloidal spheres confined within cells of different shapes formed with two slides under capillary forces are studied. It is found that by controlling the shape of the cell the curvature of the drying front can result in a significant effect on the self-organization process. A curved drying front formed within parallel slides is always associated with growth of colloidal crystal structures with a high density of disorder. We demonstrate that single-domain two-dimensional colloidal crystals with centimeter size can be grown under capillary forces under a straight drying front formed in a wedge-shaped cell. These findings are demonstrated by laser diffraction, microscopy imaging methods and off-normal optical transmission measurements. The present growth method should be of importance in expanding colloidal crystal applications in angle-resolved nanosphere lithography, as well as in preparation of high-quality quasi-three-dimensional plasmonic crystals.