Materials and Cavity Design Principles for Exciton-Polariton Condensates.

Exciton-polariton condensation offers a promising path to low-threshold coherent light sources, impacting fields from communications to healthcare. These hybrid quasiparticles, arising from strong exciton-photon coupling, combine the low effective mass from their photonic component and the strong nonlinear interactions from excitons. While polariton condensation has been achieved in a range of inorganic and organic materials, many systems still face significant challenges despite fulfilling the main properties requirements. In this perspective, we examine condensation mechanisms across different materials and highlight that universal guidelines do not exist; instead, we believe that exciton-polariton condensation is governed by the intrinsic properties of the active material. We propose using 2D perovskites as versatile platforms to investigate how specific structural and electronic characteristics influence the nonlinear processes driving exciton-polariton condensation. By exploiting the versatility of 2D perovskites, we can systematically explore and establish universal principles guiding the realization of polariton condensation in various material systems.