Polarization-Independent Dispersive Complex-Amplitude Modulation via Anisotropic Metasurfaces

Abstract

Polarization-independent characteristic is highly desirable for practical applications, and for metasurfaces, it is typically achieved through isotropic structures. This inevitably leads to a lost degree of freedom (DoF) within the parameter space, thereby restricting the realization of advanced functionalities in a polarization-independent regime. Here, counterintuitively, polarization-independent dispersive complex-amplitude modulation is achieved via a single-layered anisotropic metasurface. By fully exploiting the in-plane DoFs in the parameter space, the previously unattainable polarization-independent functionalities can be achieved without adding additional challenges to metasurface manufacturing. The underlying mechanism relies on the optimization of the superimposed dispersive Jones matrix of the meta-molecule, which demonstrates identical behavior under a pair of orthogonal polarization bases. As a proof of concept, polarization-independent color printing is numerically and experimentally demonstrated, which is completely different from the resonant structural color that depends on the optimization of spectral characteristic. Moreover, the integration of near-field color printing, far-field color holography, and an achromatic multi-port beam splitter with arbitrary power ratio are demonstrated as well. The proposed metasurface platform opens up new doors for designing polarization-independent compact meta-devices, holding various applications in augmented-reality displaying, information communication, and optical security.