Four-level polarization discriminator based on a surface plasmon polaritonic crystal

A compact, four-level polarization discriminator based on a surface plasmon polaritonic crystal (SPPC) has been experimentally demonstrated. It is able to uniquely resolve and spatially separate four signals that have been linearly polarized at azimuth angles 0°, 45°, 90°, and 135°. It exploits the excitation of multiple surface plasmon polariton eigenmodes in nondegenerate directions when the SPPC is illuminated with monochromatic light. The device is planar and of micrometer scale, which makes it suitable for on-chip integration and miniaturization of photonic circuits.