Physics of Bragg Mirrors

This lecture introduces Bragg mirrors, also known as distributed Bragg reflectors (DBRs), as an alternative to metallic mirrors, achieving reflectivities over 99%. The physics behind DBRs, based on optical thickness and constructive interference, is explained. Specific features of DBRs are discussed, followed by a review of Fabry-Perot cavities. Planar microcavities, the microscopic counterparts of Fabry-Perot cavities, are introduced, emphasizing photon storage for light-matter interaction. The lecture touches on weak and strong coupling regimes in the context of Bragg mirrors. Examples of DBRs are provided, showcasing their high peak reflectivity and compatibility with epitaxial requirements.