Nontrivial band geometry in an optically active system

Abstract Optical activity, also called circular birefringence, is known for two hundred years, but its applications topological photonics remain unexplored. Unlike the Faraday effect, optical activity provokes rotation of linear polarization light without magnetic effects, thus preserving time-reversal symmetry. In this work, we report a direct measurement Berry curvature and quantum metric photonic modes planar cavity, containing birefringent organic microcrystal (perylene) exhibiting emergent activity. This experiment, performed at room temperature visible wavelength, establishes potential materials implementing non-magnetic low-cost devices.