Broadband Generation of Polarization-Immune Cloaking via a Hybrid Phase-Change Metasurface

Metasurface-enabled cloaking offers an alternative platform to render scatterers of arbitrary shapes indiscernible. However, specific propagation phases generated by the constituent elements for cloaking are usually valid for a single or few states of polarization (SOP), imposing serious restrictions on their applications in broadband and spin-states manipulation. Moreover, the functionality of a conventional metasurface cloak is locked once fabricated due to the absence of active elements. Here, we propose a hybrid phase-change metasurface carpet cloak consisting of coupled phase-shift elements setting on novel phase-change material of Ge2Sb2Se4Te1 (GSST). By elaborately arranging meta-atoms at either 0 or 90 degrees on the external surface of the hidden targets, the wavefront of its scattered lights can be thoroughly rebuilt for arbitrary SOP exactly as if the incidence is reflected by a flat ground, ensuring the targets' escape from polarization-scanning detections. Furthermore, the robustness of phase dispersion of meta-atoms endows the metasurface cloak wideband indiscernibility ranging from 7.55 to 8.35 mu m and tolerated incident angles at least within +/- 25 degrees. By reversibly switching of the phase states of Ge2Sb2Se4Te1 , the stealth function of our design can be turned on and off. The generality of our approach will provide a straightforward platform for polarization-immune cloaking, and may find potential applications in various fields such as electromagnetic camouflage and illusion and so forth.

Automated summary

Metasurface-enabled cloaking offers an alternative platform for rendering scatterers of arbitrary shapes indiscernible, with broadband and spin-states manipulation capabilities. The hybrid phase-change metasurface carpet cloak proposed in this study provides wideband indiscernibility and can be controlled by switching the phase states of the phase-change material.