Dynamically switchable polarization-independent and broadband metasurface perfect absorber in the visible and near-infrared spectra regime

An electrically tunable absorber in the visible (Vis) and near-infrared (NIR) regime is theoretically investigated. The absorber is composed of aluminum (Al)-indium tin oxide (ITO) composite square pillars on top of thin dielectric layer and Al substrate. Significant tuning of absorption with modulation ratio of 86% can be achieved. The modulation ratio above 75% can be maintained from 1427 to 1795 nm and over 90% absorbance at the NIR regime from 1500 to 1800 nm can also be achieved. The symmetry of the absorber eliminates the polarization dependence and the near unity absorption efficiency can be maintained by incidence angles up to 70°. The presented method will enhance the functionality of absorber and has the potential for the applications that require active control over light absorption.