Strongly Coupled Organic Microcavities

The photophysics of planar microcavities which employ organic materials as the optically resonant medium to achieve the strong-coupling regime is discussed. While as a result of the light–matter coupling, cavity polariton branches appear which are analogous to those observed in inorganic microcavities, many properties of organic-based microcavities are qualitatively and quantitatively different. The electronic excitations involved are molecular Frenkel excitons, rather than large radius Wannier excitons, which lead to large Rabi splitting values. The effects of disorder are typically much more pronounced as well as the exciton-phonon coupling, possibly leading to vibronic replicas. As a consequence, polariton relaxation and polariton-polariton scattering mechanisms also show features specific to the organic material employed. The field of organic-based microcavities is attracting an increasing interest as high excitation density phenomena such as polariton lasing have recently been reported. In view of their experimental relevance, two different kinds of organic microcavities, disordered J-aggregate-based microcavities and crystalline anthracene microcavities, are considered.