Changchun Yan

Polarization-independent broadband plasmonic absorber based on a silicon-nanowire array decorated by gold nanoparticles at the optical regime

We present a design for a plasmonic absorber that is composed of a hexagonal-packed silicon nanowires (SiNWs) array with gold nanoparticles (AuNPs) decoration. Simulations and experiments demonstrated that the proposed absorber achieves a broadband absorption. Its bandwidth over an absorption of 80% ranges from 400 nm to 1000 nm at 0 degree to 30 degrees incidence. It was also demonstrated that the plasmonic absorber is polarization-insensitive. Analyzing the field distributions in the structure, we find that the wideband absorption is ascribed to the formation of cavity modes in the SiNWs and surface plasmon polaritons on the AuNPs. Such a designed plasmonic structure with high-efficiency absorption can be served as a good optical absorber.

Switchable reflection/transmission utilizing polarization on a plasmonic structure consisting of self-assembly polystyrene spheres with silver patches

We report a plasmonic structure for switchable reflection and transmission by polarization. The structure is composed of a hexagonal-packed polystyrene sphere array with silver patches on them. Simulations and experiments demonstrated that the conversions between reflected beams and transmitted ones can be performed when the polarization directions of incident beams vary from 0° to 90°. A switchable reflection and transmission at a given wavelength can be obtained, as long as sizes of PS spheres and azimuthal angles are properly chosen. Such a patchy plasmonic structure serving as a switch between reflection and transmission have potential applications in photoelectric control devices.