Plasmonic directional beam switching with tilted nanoslit array surrounded by gratings

We propose a scheme for directional beam switching from line-envelope tilted nanoslit array surrounded by gratings. The line-envelope nanoslit array composed of double arrays of tilted nanoslits can be utilized for directional launching of surface plasmon polaritons (SPPs). On the left and right side of the nanoslit array, metallic gratings are asymmetrically carved in order to design the diffracted lights from the gratings in different beaming angles according to the incident polarization states. Both numerical and experimental results verify that the beaming angles from the proposed structure follow the diffraction theory of surface gratings, and the extinction ratio between two beams can be switched by tuning of the incident polarization. We expect that the proposed beam switching mechanism can be applied to the basic platform of tunable SPP-based radiation or nanoantenna manufacturing.