Independent adjustment of the transmission amplitude and phase based on the double-sided all-dielectric encoding metasurface

In order to achieve high-efficiency and independent control of the amplitude and phase of light transmitted from the coded metasurface, we propose a double-sided all-dielectric unit structure. The all-dielectric metasur-face unit structure is composed of a silicon dioxide substrate with silicon elliptical cylinder and silicon cylinder on both sides. The phase of the transmitted light can be adjusted by rotating the elliptical cylinder, and the amplitude of the transmitted light can be adjusted by changing the radius of the cylinder. In order to obtain the ideal amplitude and phase control, we set the initial rotation angle of the elliptical cylinder to eliminate the additional phase, which is caused by the radius change of the nanocylinder. We can digitally encode the unit structure of the elliptical cylinder with different rotation angles to construct different sequences of encoded metasurfaces. By adjusting the structural parameters of the encoded particles in the encoding metasurface, the amplitude and phase of the transmitted beam can be independently adjusted. The independent modulation of amplitude and phase of coding particles is verified by the far-field scattering characteristics of different coding metasurfaces.