Edge optical effect as a probe of chiral topological superconductors

Abstract: We study the optical effect of chiral topological superconductors in two dimensions. The linear optical response from chiral Bogoliubov edge modes in clean superconductors has in-gap resonances, which is originated from the transitions within the edge particle-hole pair bands. Interestingly, the number of resonance peaks is determined by the Bogoliubov-de Gennes Chern number of topological superconductors. Such a sharply distinctive feature in optical absorption offers a simple way to distinguish topological superconductors with different Chern numbers. We further demonstrate that linear optical effect could probe different topological phases in quantum anomalous Hall insulator-superconductor junction devices. This finding provides an applicable method to detect chiral Bogoliubov edge states and is distinguishable from collective modes in superconductors and possible trivial explanations.