Topologically Enhanced Circular Dichroism from Metasurfaces

Obtaining strong circular dichroism (CD) from planar chiral metasurfaces has been hotly pursued, to realize ultracompact circular polarizers for applications in photography, spectroscopy, and biological sensing. Many attempts have failed, due to insufficient thickness of the structures. Here the authors present efficient enhancement of the CD response from a metasurface by utilizing its topological edge state. One can foresee a direct impact of this result on engineering solutions for the applications mentioned above.