Topological Exciton Polaritons in Compact Perovskite Junction Metasurfaces

Abstract Exciton polaritons are hybrid light‐matter quasi‐particles that hold exceptional opportunities for future optoelectronic devices. Taking the synergic advantages of room‐temperature perovskite excitons and topological photonic structures, topological exciton‐polaritons are experimentally demonstrated in organic–inorganic hybrid perovskite thin films. Topological junction structures based on perovskite gratings are realized using a momentum‐space analog of the 1D Dirac system. Desired enhancement phenomena are observed including narrow‐beam polariton emission from a tightly localized junction region, polaritonic nonlinearity boost, and enhanced luminescence. These remarkable features are obtained from highly compact devices with footprint widths on the order of a few micrometers and are efficiently tailorable with simple unit‐cell geometry control. Therefore, the proposed approach can be a powerful platform for room‐temperature topological exciton‐polaritons and concomitant device applications.