Dynamic studies of polariton modes in a vdW magnet

Van der Waals materials have been shown to support a wide range of polaritons with unique properties, like twist-angle dependent propagation in α-MoO₃ or gate-tuned wavelength in graphene. In some vdW antiferromagnets, exciton-polaritons play a major role in the optical response, and can be strongly affected by the underlying magnetic order. Here by employing a combination of steady-state and ultrafast optical techniques we probe the time-resolved transport and magnetic coupling of such polariton modes. These techniques have allowed us to identify a range of novel behaviors, which opens the door to further engineering of light-matter interaction in these systems.