Chiral Meta-Coder for Spin Switchable Electromagnetic Camouflage and Information Authentication

Electromagnetic camouflage is crucial for concealing the physical identity of the object from external electromagnetic detection, whether in military operations or civilian contexts. However, addressing the pressing issue of seamlessly transitioning between camouflage and visualization capabilities is a significant challenge. By combining chiral meta-atoms and irregular phase encoding method, a novel chiral meta-coder is proposed for spin switchable electromagnetic camouflage and target authentication. Different from traditional conformal strategies, this meta-coder achieves camouflage functionality by tightly arranging meta-atoms around the target object and encoding suitable phase sequences to shape desired wavefront. Simultaneously, the target object can also be identified by modulating the helical state of the incident wave. As a proof of concept, a chiral meta-coder operating in camouflaging “A” shaped target object is designed and experimentally demonstrated. When exposed to right circularly polarized waves, the meta-atoms surrounding the object can adapt the wavefront to conceal target information. The camouflaged pattern exhibits diffuse scattering in the far field and three focal patterns around the near field. Conversely, these meta-atoms transition into a wave-absorbing configuration, facilitating the precise identification of target information. Such a strategy may find potential applications in data security, privacy, and communication.