Steering surface plasmons with a graded index dielectric medium

The arbitrary control of surface plasmon (SP) propagation has become an intense research topic for several decades. This is due to the fact that they can be used in a variety of fields such as optical trapping, nanoantennas and medical applications. In this communication, the graded index technique is applied in the design of several steerers able to tailor the direction of propagation of the incident SPs by simply changing the height of a dielectric block on top of a semi-infinite metal slab. The design procedure is shown and the structures are numerically evaluated demonstrating a good agreement with the analytical calculations, with the SPs deflected at the design angles (theta ranging from 10 degrees to 60 degrees) with a wide bandwidth steering of 60 nm around the design value (633 nm).