An original and promising technology for guiding surface plasmons has been developped in the group of Prof. S.I. Bozhevolnyi at Aalborg University, where a combination of photonic crystals and metallic waveguides is used.

The left group of four pictures shows a double bent realized with this technology: Top row: topographical images of 3-micron-wide and 25-micron-long channels containing double bends (with the bend angles ranging from 5 to 30 degrees) in a 410-nm-period triangular lattice of 200-nm-wide and 45-nm-high gold scatterers (not resolved) fabricated on a 45-nm-thick gold film surface. Bottom row: near-field optical images obtained with a scanning near-field optical microscope of the surface plasmon-polariton propagation (upwards) excited resonantly at the wavelength of 737 nm. The near-field optical images illustrate plasmon-polariton propagation along sharply bent channels with relatively low loss as well as strong field confinement within the channels due to the photonic band gap effect.

The right group of pictures shows Y-junctions realized with this technology.

Images courtesy of Prof. S. I. Bozhevolnyi, Department of Physics and Nanotechnology, Aalborg University, Denmark.