The Quantum optics tag covers research and applications where the quantum nature of light plays a central role, such as single-photon sources, entanglement experiments, and nonclassical light generation. Articles may discuss experimental setups that rely on high-stability lasers, precise interferometers, and low-loss optical paths to observe and exploit quantum phenomena. Topics can include photon statistics, squeezed light, quantum interference, and their potential applications in sensing, communication, and computation. Readers see how specialized optics and careful design are required to preserve fragile quantum states and achieve meaningful signal-to-noise ratios. For scientists and engineers interested in quantum technologies, this tag provides a window into the practical optical considerations that underlie quantum optics experiments and devices. It also suggests how Avantier’s custom optics capabilities can support these advanced photonic systems.