Excitons, Photons and their Couplings

Abstract

The book « Excitons, Photons and Their Couplings » gives an enlightening presentation of elementary semiconductor excitations, the excitons, through their couplings to photons. Starting from the basic principles of solid state physics, this book provides a general introduction to semiconductors, a fascinating material not only for technological applications but also for fundamental physics, as well as to the electromagnetic field, classical or quantum. Through Coulomb interaction between its two key particles, the electron and the hole, that is, conduction electron and valence electron absence, a subtle physics develops that differentiates bright from dark excitons. Within a quantum formulation of the exciton-photon interaction, the exciton and photon are shown to form a long-lived coupled mode, the polariton. To prevent polariton formation and possibly create excitons through photon absorption, the exciton must change its wave vector through collisions in the semiconductor sample that acts as an open system. The exciton photocreation results from a subtle competition between exciton coupling to photons and exciton wave vector relaxation. A book dealing with fundamental semiconductor physics, published in 2025, is expected to reconsider well accepted results and derivations and provide fresh insights. The present book does provide original presentations of many fundamental questions. As such, it should be of interest not only for students to learn from cleaner calculations, but also for advanced physicists to question their knowledge, as the authors have done.