Optical spin angular momentum sensitivity of topological nanoflakes

Two-dimensional Chern insulators, characterized by broken time-reversal symmetry and chiral edge states, are a promising platform to engineer exotic light-matter interactions. While most previous studies focused on bulk optical properties in extended media, investigations uncovering the unique photonic features of finite topological structures have been rare. In this work, we consider the optical response in nanoflakes of the prototypical Haldane model, which describes graphene-like systems where time reversal and sublattice symmetry breaking drive a topological phase. A simple argument elucidating the interplay between these fundamental properties and the optical spin angular momentum (SAM) of external light singles out these nanoflakes as prime candidates for SAM-sensitive optics. Building on these insights, we conduct a linear response analysis which reveals highly selective optical behavior, manifesting in strongly enhanced preferential absorption. Our results bridge topological materials and photonics, highlighting a direct link between topological properties and characteristics of electromagnetic radiation.