Transmission enhancement with the array of faced folded metallic rods embedded in a metallic slit

We propose that the array of plasmonic faced folded rods (FFR) enhances transmission of light in a narrow metallic slit. The FFR unit can play the role of light concentrator at the visible regime. Diffracted light from a sub-wavelength metallic slit can be transmitted into a far-field region and enhance light intensity when the array of FFRs is placed inside the metallic slit. Additional transmission enhancement from the FFR structure can be obtained from the localized couplings between FFR and its adjacent FFRs. Numerical approach using a rigorous coupled-wave analysis technique is adopted, and the functionality is shown by the use of optical microscopy which provides far-field intensity images emanating from the array of FFRs embedded in a metallic slit.