Broadband metamaterial absorber with optically controlled switching for tunable electromagnetic absorption

Abstract This paper presents the design, fabrication, and characterization of a broadband metamaterial absorber (MMA) capable of optical switching between high- and low-absorbing states. The proposed metasurface exhibits a wide absorption bandwidth ranging from 13 to 17.3 GHz, maintaining a high absorption for wide incidence angles and for both transverse electric and transverse magnetic polarizations, demonstrating the polarization-insensitive performance. The metasurface is composed of periodically arranged unit cells integrated with photoresistors that enable tunable electrical resistance under optical illumination. When exposed to light, the photoresistors reduce their resistance, allowing the structure to achieve a high absorption. In the absence of illumination, the increased resistance suppresses the absorption response, effectively switching the metasurface to be a reflective state. This optically controllable behavior provides a simple and efficient approach for realizing dynamically reconfigurable MMAs, offering potential applications in adaptive stealth technology, electromagnetic shielding, and tunable sensing systems.