Abstract:

Electron-hole pairs (excitons) and light can interact when a semiconducting material is placed inside a Fabry-Perot (F-P) cavity. The Purcell effect dominates when the light-matter interaction is weak. However, in cases where the exciton transition energy is resonant with one cavity mode, and the light-matter interaction rate exceeds any energy dissipation pathways, then the system enters the strong coupling regime. In this case, hybrid states of excitons and photons (known as exciton-polaritons) will be formed, causing the exciton energy to split into two new energy levels. Exciton-polaritons inherit both excitonic features, e.g., interaction with optically inactive materials, and photonic features, e.g., delocalization. Due to these unique characteristics, exciton-polaritons show great potential in the modification of materials' physical and chemical properties, such as energy relaxation, propagation and so on. They also enable interesting phenomenon, such as Bose-Einstein condensation, superfluidity and so on. In this seminar, I will briefly introduce the recent progress on polariton studies and discuss the possible design of a broadband polariton system in a multi-layer F-P cavity.