Wafer-scale ultra-broadband perfect absorber based on ultrathin Al-SiO stack metasurfaces.

Broadband absorbers with high absorption, ultrathin thickness, and lithography-free planar structure have a wide range of potential applications, such as clocking and solar energy harvesting. For plasmonic metal materials, achieving perfect ultra-broadband absorption remains a challenge owing to the intrinsically narrow bandwidth. In this study, wafer-scale Al-SiO stack metasurfaces were experimentally fabricated to realize perfect ultra-broadband absorption.