Design And Study On Functional Photonic Devices Based On Metasurfaces

Metasurface is a planar sub-wavelength scale metamaterial with ultra-thin thickness and low loss.The most critical feature of metasurface is that they can be designed more freely on the optical interface,and adjacent antennas arrays are composed of different structures or materials.Therefore,various electrical or magnetic responses can be introduced to shape wavefront to achieve different beam functions.This thesis includes two main studyes.Firstly,we design a chiral metasurface based on sub-wavelength nanorods arrays to realize asymmetric optical transmission.Secondly,we propose a series of dual-wavelength multifunctional metadevices based on modularization design by using indium-tin-oxide to realize different beam functions.For asymmetric transmission metasurface,we demonstrate a double-layer nanorods arrays structure and carry out numerical simulations.The result indicates that based on the polarization conversion,ultra-wide,high-contrast asymmetric optical transmission can be obtained in 1310-1550 nm spectral range.In addition,when the incident angle changes from-45° to 45°,the device also exhibits good performance.Moreover,we later propose four different dual-wavelength multifunctional metadevices based on modularization design by using indium-tin-oxide.Benefiting from the fact that ITO holds high infrared(IR)refection while transparence at visible wavelengths,the metadevice can work in refection and transmission modes at two very distinct wavelengths,one is 2365 nm in the IR band and the other 650 nm in the visible range.The two metasurface layers with different functionalities are easy to integrate into a series of dual-wavelength multifunctional metadevices,without need of re-designing or reoptimizing their structure parameters.Based on modularization design and functional integration,four kinds of dual-wavelength multifunctional metadevices are demonstrated,which can perform reflective defection/focusing at 2365 nm and transmissive defection/focusing at 650 nm.We believe our work may open a straight-forward and flexible way in designing multi-wavelength multifunctional metasurface.