STUDY OF LIGHT MANIPULATION BY MULTI-FUNCTIONAL METASURFACE

Abstract

Nanostructured metasurfaces demonstrate extraordinary capabilities to control light at the subwavelength scale, emerging as key optical components to physical realization of multitasked devices. This thesis focuses on the study of multi-tasked metasurfaces that allow multiplex controls of the incident beams based on minimalist spatial freedoms. First, multi-orbital-angular-momentum (multi-OAM) meta-transformer is presented. By fully synergizing OAM of the incident light with the identical phase profile embedded in the metasurface, the multi-OAM meta-transformer converts different topologically charged beams into distinguished on-axis holographic patterns at the same plane. Second, multi-linear-momentum (multi-LM) meta-hologram is studied. Based on the dispersion relationship of propagation and the Pancharatnam-Berry (PB) phase, the designed meta-hologram is able to achieve full color images as well as 6-bit encoded color holograms. Lastly, by combining monolayer tungsten diselenide and patterned sub-20 nm-wide gold trenches, nonlinear metasurface is proposed to extend research field from linear to nonlinear responses.