Amplitude and phase independent modulation based on transmission-type metasurfaces

We propose an ultra-thin I-type metasurface that independently controls the amplitude and phase of transmitted waves simultaneously by changing the geometry and direction of rotation of I-shaped metal particles. It is found that the direction of rotation and the size of the geometrical opening of the I-shaped copper particle indepen-dently control the amplitude and phase of the incident wave. In order to better demonstrate the independent regulation of the amplitude and phase of the metasurface, we arranged the element structure and constructed a grating structure. We can adjust the diffraction order of grating freely by arranging different element structures. Using classical lithography techniques, we have experimentally prepared the array structure samples and compared the theoretical results with the experimental measurements. Theory and experiment agree well. We further propose a two-layer structure to simultaneously regulate the amplitude and phase of terahertz waves. The amplitude and phase of transmitted terahertz waves can be independently regulated by the rotation angle and opening angle of the double-layer cell structure. We further prepared the double-layer structure sample, and the theoretical calculation results are in good agreement with the experimental measurement results.