Broadband metasurface for independent control of reflected amplitude and phase

We propose an ultra-thin metasurface to control the amplitudes and phases independently of the reflected waves by changing geometries and orientations of I-shaped metallic particles. We demonstrate that the particles can realize independent controls of reflection amplitudes and phases with a magnitude range of [0, 0.82] and a full phase range of 360° in broad frequency band. Based on such particles, two ultrathin metasurface gratings are further proposed to form anomalous reflection with polarization orthogonal to the incident waves. The simulated and measured results of the presented metasurfaces show very good agreements. The proposed method has potential applications in engineering high-efficiency holography and complex electromagnetic and optical patterns.