Abstract: Chirality is usually thought of as a structural property wherein an object cannot be superposed upon its own mirror image. However, chirality can also be present as an emergent effect in condensed phase systems, especially those hosting topological order. Among the most popular examples of such emergent chirality are the parallel, spin-momentum locked quasiparticles and helicoidal dispersing surface states of the Weyl semimetals, as well as the edge states of the quantum Hall effect. In this talk, I will describe our work exploiting the emergent chirality of Weyl semimetals to search for distinctive signatures of their topological ordering through nonlinear optical response. I will also discuss our recent observation of a novel nonlinear analogue of electromagnetically induced chirality, a topologically trivial effect previously only observed at linear order in atoms, which originates here from a quantum interference between localized and itinerant electrons in a structurally achiral system that is only visible at second order.
The College of Arts