Analytical full complex-amplitude control strategy for metasurface

We proposed a meta-atom design strategy that can achieve full complex-amplitude modulation based on analytical method for circularly polarized waves. The meta-atom can be regarded as two cascaded quarter wave plates, the orientation angles of which provide two degrees of freedom for obtaining arbitrary amplitude and phase modulation through accurate analytical method. As verification, a microwave meta-atom is designed and used to realize lateral and axial dual focusing. The proposed design strategy provides a straightforward route for full, continuous control of both amplitude and phase, and can stimulate various advanced meta-devices. (paper)