Polarization superprism effect in surface polaritonic crystals

Surface plasmon polariton waveguide modes excited in mutually orthogonal line defects of a surface polaritonic crystal (two-dimensional photonic crystal on a metal surface) are observed to be extremely sensitive to the polarization state of excitation light. Full switching between orthogonal waveguides can be achieved with less than 10° variation of the polarization angle. For oblique incidence, the polarization sensitivity of switching is even higher but full switching cannot be realized. This effect can be considered as a polarization-domain analog of the photonic crystal superprism effect. It suggests the possibility of building actively controlled photonic crystal devices for optical signal processing.