Multi-functional polarization imaging and optical encryption of diatomic metasurfaces by using transfer matrix analysis

Abstract

The multi-functionalities of metasurface structure usually need to increase a high system complexity and a low efficiency, which can be mathematically expressed by the transfer matrix. This study presents an all-dielectric diatomic metasurface design approach, deduced from the transfer matrix to achieve high degrees of freedom and multifunctionalities in multimodal polarization imaging analysis. Here a compact and efficient all-dielectric diatomic metasurface platform is proposed, which can effectively achieve the selectivity of arbitrary orthogonal polarization. It is proved that the phase and amplitude of two orthogonal circular polarizations can be controlled independently by designing the rotation angle relationship between the diatoms. Furthermore, we propose an optical polarization imaging encryption that generates four near-field amplitude and far-field diffraction holograms, which can only be observed when the incident light is at a specific polarization state, whereas no image can be discerned for the orthogonal polarization incidence case, indicating the realization of incidence-polarization secured meta-image. Through data fusion, we are able to combine multiple polarization imaging modes to improve the accuracy and security of information. We envision the metasurface to enhance the security of information transmission and open new possibilities for creating compact multifunctional optical devices for optical data storage and security.