Circular dichroism in higher-order harmonic generation: Heralding topological phases and transitions in Chern insulators

Abstract

The future technological revolution in the production of ultrafast devices lies in the control of materials that will speed-up transistors. The recent discovery of topological states of matter promises a unique opportunity to address this challenge. However, the control and diagnostics of topological materials remain hard to achieve. Here, the authors show an alternative to distinguish a topological phase by its nonlinear-light circular dichroism (CD): the asymmetry of the material-light emissivity while the topological phase is subjected to right-circularly (RCP) and left-circularly polarized (LCP) mid-infrared lasers. This CD exhibits striking distinction in a topological phase, as depicted in the schematic.