Bend loss for channel plasmon polaritons

Using near-field optical microscopy, the authors investigate propagation of channel plasmon polaritons excited in the wavelength range of 1425–1640nm along smoothly bent and split V-shaped grooves milled in a gold film. We find that for 0.6-μm-wide and 1.1-μm-deep grooves bent with the smallest curvature radius of ≅0.83μm, the double bend (for S bends) and splitting (for Y splitters) losses decrease for longer wavelengths approaching (in the wavelength range of 1600–1640nm) the levels of ∼0 and 0.5dB, respectively.