Metal-dielectric metamaterials for guided wave optics applications

摘要

We address the experimental validation of the technological feasibility and operation of the metamaterials in a guided wave configuration in the spectral domain around 1.5μm. For our experiments we considered a 2D array of 200×50×50nm gold cut wires placed on the top of a 10μm wide and 200nm thick silicon waveguide. The transmission spectral measurements performed in the spectral range between 1.25 and 1.64μm using an end-fire coupling setup, revealed a marked dip for TE polarized light, corresponding to the cut wires resonance frequency obtained by numerical modeling. No such a dip in transmission was observed for TM polarized light, i.e. when the electric filed is perpendicular to the layers interface and the orientation of the cut wires. The scanning near field optical microscopy experiments (SNOM), performed in the same spectral range, revealed for TE polarized light a strong enhancement of the electric field confined in the region between the ends of the adjacent cut wires. These results confirm the efficient excitation of the cut wires resonance in a guided wave configuration for the TE polarization. The ability for local engineering of the field interaction with the metamaterial layer and thus the control in such a way of the light flow in a guiding slab, paves the way to a novel class of photonic devices.