Functional control of anomalous reflection via engineered metagratings without polarization limitations

TL;DR

This paper introduces an inverse-design method for simple metagratings that can control electromagnetic wave reflection without polarization constraints, enabling advanced wavefront and polarization manipulation.

Contribution

The work presents a novel inverse-design approach for flat metal surface metagratings that achieve polarization-independent anomalous reflection with simple structures.

Findings

Achieves perfect retroreflection and specular reflection

Enables polarization-dependent and polarization-independent retroreflection

Confirmed through full-wave simulations

Abstract

Metagratings (MGs) have emerged as a promising platform for manipulating the anomalous propagation of electromagnetic waves. However, traditional methods for designing functional MG-based devices face significant challenges, including complex model structures, time-consuming optimization processes, and specific polarization requirements. In this work, we propose an inverse-design approach to engineer simple MG structures comprising periodic air grooves on a flat metal surface, which can control anomalous reflection without polarization limitations. Through rigorous analytical methods, we derive solutions that achieve perfect retroreflection and perfect specular reflection, thereby leading to functional control over the linearly-polarized electromagnetic waves. Such capabilities enable intriguing functionalities including polarization-dependent retroreflection and polarization-independent retroreflection, as confirmed through full-wave simulations. Our work offers a simple and effective method to control freely electromagnetic waves, with potential applications spanning wavefront engineering, polarization splitting, cloaking technologies, and remote sensing.