excitonpolaritonen

An excitonpolariton is a quasiparticle that arises from the strong coupling between a photon and an exciton. An exciton is a bound state of an electron and an electron hole in a semiconductor, representing an excited state of the material. A photon is a quantum of light. When a photon interacts strongly with an exciton, their wavefunctions hybridize, forming a new entity that possesses properties of both the photon and the exciton. This mixing results in a new energy-momentum dispersion relation, where the upper and lower polariton branches are formed.

The properties of excitonpolaritons are distinct from those of their constituent quasiparticles. They exhibit reduced mass compared to excitons and can travel macroscopic distances, similar to photons, while retaining some of the strong optical nonlinearity associated with excitons. This hybrid nature makes them promising candidates for applications in low-threshold lasers, Bose-Einstein condensates, and other quantum optical devices. The phenomenon of strong coupling, leading to the formation of excitonpolaritons, typically occurs when the exciton's transition frequency is close to the frequency of light confined within a resonant optical cavity. The strength of the coupling determines the degree of mixing between the photon and exciton components.