Polarization-Independent Wavefront Manipulation of Surface Plasmons with Plasmonic Metasurfaces

Plasmonic metasurfaces show great potential to manipulate the wavefront of surface plasmons (SPs) and enable realization of various chip-level photonic devices. However, the current configurations can merely operate under specific incident polarization state and/or have limitation in independently tuning the phase and amplitude of SPs, although arbitrary incident polarization state is allowed. There is still the lack of a metasurface scheme that not only can couple spatial light waves into SPs under arbitrary polarization states, but also can independently modulate the amplitude and phase of the generated SPs. Here, it is proposed and experimentally demonstrated that double-lined metallic nanoslits can be well designed to overcome these limitations. Practical metadevices are designed and fabricated for generating polarization-independent plasmonic Airy beams, near-field focusing, and intensity-preserved lossless beams, and their excellent performances at 633 nm are characterized with near-field scanning optical microscope. The presented results will offer opportunities for the practical plasmonic devices and applications based on the plasmonic metasurfaces.