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.