Sub-wavelength quarter-wave plate based on plasmonic patch antennas

A quarter-wave plate using plasmonic patch antennas has been investigated. The nanostructures can convert linear polarized light into circular polarized light in the visible range (633 nm). By further exploiting the dimer patch antenna structure composed of different metals, directional emission (with a directivity of 4.8) of circular polarized light (with a conversion efficiency of 27.8%) in an oblique direction with respect to the incident light is enabled. Compared with previous designs, the proposed structures are ultra-thin, and are more suitable for integration applications. (C) 2013 AIP Publishing LLC.