Manipulation of the Steering and Shaping of SPPs via Spatially Inhomogeneous Polarized Illumination

In this paper, we demonstrated a far-field scheme for the manipulation of locally excited surface plasmon polaritons (SPPs). This scheme features steering and shaping capabilities, and relies on the focusing of a high numerical aperture, in conjunction with spatially inhomogeneous polarized (SIP) illumination. We were able to control the propagation and direction of SPPs, via the field distribution of polarization at the entrance pupil, without the need for an aperture, protrusion or any other near-field features. Depending on the axial position of the focus, the field distribution of excited SPPs revealed either counter-propagating interference or a multi-casting plasmonic source. The results of near-field imaging demonstrated the versatility of the SPPs, showing strong agreement with the predictions made during simulations. Due to the simplicity and versatility of the proposed method, we believe that it could have a significant impact the processes employed in the excitation of a variety of SPPs.