Strong light-matter interactions and exciton-polaritons in organic materials

Abstract This chapter discusses strong light-matter coupling in organic materials. This is a regime where the interaction between photons and matter excitation is large enough to form polaritons, which are part-light and part-matter quasiparticles. Polaritons form when photons strongly couple to an element such as plasmons, phonons, or excitons. Here, we focus on the coupling of microcavity photons to excitons of a material that is placed in the microcavity, so-called exciton-polaritons, which are seen as promising candidates to realize room-temperature, low-threshold lasers, quantum simulators, and chemical landscape engineering. First, we introduce the concept of exciton-photon hybridization and the physical phenomena emerging from this. Next, we review the organic materials that have so far been investigated in the context of strong light-matter coupling and to study the mixing of different excitonic and vibronic states. We also discuss electrical pumping of exciton-polaritons and condensation of polaritons into their common ground state, a process that gives rise to inversionless, laserlike emission.