Flexibly Optical Manipulation Based On Tunable Anisotropic Metasurface

In this paper,we propose a kind of two-dimensional tunable metamaterial with relatively large anisotropy.We first introduce the design methodology of the metamaterial unit in bulk medium,then demonstrate some applications of metasurface.The bulk metamaterial unit constructed with single dielectric material can processes higher agility and larger anisotropy.The optical axis orientation of the metamaterial unit can be tuned to achieve the different properties of the unit cell.By Transmission and Reflection(TR)retrieve method and average field method,we get the effective medium parameters of the metamaterial unit,which demonstrates the validity and feasibility of our approach.Combinating such tunability of the metamateial and Transform Optics(TO),we can realize a kind of TO devices,such as beam shifter.With the principle of this tuable metamaterial,we design the metamaterial unit mixing with metal and dielectric to build a tunable metasurface to realize multiple functions,which are based on merely changing the optical axis of each unit cell.By simply rotating the orientation of the unit cell optical axis,it can provide continuous reflected phase shift over 2? span since the unit cell is with relatively large anisotropy.It supplies the theoretical phase-shift profile governed by generalized Snell's law of metasurfaces with different functions.We can arranging the unit cells with different optical axis orientations in right sequences in a row,then the intriguing optical phenomenas,such as illusion,focusing and skin cloaking,can be realized and demonstrated by finite-element simulations.We believe that the approach paves an alternative way for wavefront modulation and optical manipulation.