Planar Freeform Metasurfaces with Customized Circular Dichroism Responses

Abstract

Chiral metasurfaces have emerged as a versatile platform for manipulating chiral light-matter interactions in diverse applications. However, the design of arbitrary chiroptical responses remains challenging because conventional parameterized geometries severely constrain the accessible design space. To address this issue, we present a design framework for planar freeform chiral metasurfaces (FCMs) in the near-infrared regime, enabling on-demand inverse engineering of customized circular dichroism (CD) responses. The proposed framework allows flexible control over key CD spectral characteristics, including spectral feature position, amplitude, line shape, and bandwidth. Experimental and numer..