OAM vortex wave interaction with phase modulated metasurface

Phase modulated metasurface (PMM) can control the transmission state of electromagnetic (EM) wave through phase modulation scheme on the interface. Orbital angular momentum (OAM) vortex wave is denoted by the helical phase distribution of the wave front. The interaction between OAM vortex wave and PMM is investigated in this paper. The mathematical model is firstly established according to the array theory. Whereafter, two typical PMMs of chessboard metasurface (CBM) and phase gradient metasurface (PGM) are exploited as examples to uncover the scattering characteristics under illumination of OAM vortex wave. For CBM, the phase cancellation scheme is found to be broken when the OAM order l equals to ±2 under both normal incidence and oblique incidence. It reveals that the OAM vortex wave is a promising approach for metasurface stealth target detection. For PGM, the scattered wave still keeps the OAM feature but is deflected to the non-specular direction, which reveals that the generalized Snell’s law is also suitable to OAM vortex wave. The discoveries of this paper may find applications in radar detection fields using OAM vortex wave.