Hyperbolic polaritons are hybrid light–matter quasiparticles that arise in extremely anisotropic materials. They can channel energy in specific directions and control light far below the diffraction limit. Their study began with artificial metamaterials, but natural hyperbolic materials have shifted attention to intrinsic, low-loss and tunable platforms.

This review sets out a framework that unifies hyperbolic polaritons across zero- to three-dimensional systems, including shear, ghost and topological edge modes, and discusses topological transitions and anomalous transport at interfaces. It also outlines a path towards integrated polaritonic circuits. Zhipei Sun of QMAT's Photonics group at Aalto University co-authored the review with researchers at China's National Center for Nanoscience and Technology, Shanghai Jiao Tong University and ICFO in Barcelona.

Image: QMAT