Local and Nonlocal Pathways to Quantum Light with Quantum Photonic Materials

ABSTRACT Advances in materials science continue to shape photonic quantum technologies. The generation and control of quantum light across diverse material platforms provide quantum resources, including single‐photon emission, complex entangled states, and hybrid interfaces between photons and other quantum systems. These resources underlie quantum communication, quantum computing, and precision metrology. Understanding material properties drives progress in quantum materials engineering. This review surveys physical origins and control strategies of quantum‐optical phenomena in materials. The mechanisms that govern the quantum properties of photons are categorized into two types. The first comprises localized effects from intrinsic quantum confinement, exemplified by quantum dots, localized excitons in transition‐metal dichalcogenides (TMDs), and deep‐level defects in hexagonal boron nitride (hBN). The second involves nonlocal collective coherent processes, particularly nonlinear responses in low‐dimensional materials. Building on these mechanisms, approaches to manipulate local states include electrostatic gating, magnetic‐field tuning, and strain engineering. Nonlocal properties are controlled by symmetry engineering and phase matching. A unifying perspective is material–mode co‐design. Nanophotonics provides optical modes from tightly confined plasmonic fields to the nonlocal character of quasi‐bound states in the continuum (q‐BICs), matching specific material platforms. This material–mode “selection rule” provides a guideline for material choice and device design, enabling versatile quantum light sources for diverse applications.