Structured light-matter interaction in semiconductor cavity quantum electrodynamics.

A cavity quantum electrodynamics system consisting of a confined single photon and a single quantum emitter serves as a fundamental block for quantum optics and photonic quantum technologies. The canonical optical mode used in the conventional cavity quantum electrodynamics features a uniform polarization distribution, leading to the scalar light-matter interaction in most existing experiments. Despite the rapid progress in the generation of structured light with spatially varied polarizations, the structured light-matter interaction, especially at the single-quanta level, is highly intriguing yet largely unexplored. Here we present the structured light-matter interaction at the single-photon level in a semiconductor cavity quantum electrodynamics system. Four distinct structured cavity modes that are spectrally close to each other are constructed in a micropillar cavity. By spatially locating a single epitaxial quantum dot (InAs quantum dot) at the periphery of a semiconductor micropillar cavity and spectrally tuning the quantum dot emission wavelength into the resonances of the structured cavity modes, cavity-enhanced single-photon emissions with spin-locked chiral orbital angular momentum and engineerable spin-orbit entanglements are achieved within a single wavelength-scale device. Our work opens different ways of exploring structured quantum light-matter interactions in chiral quantum optics and high-dimensional photonic quantum technology.