Low-dimensional quantum materials, including quantum dots, one-dimensional nanowires, two-dimensional van der Waals crystals, quantum wells, and their engineered heterostructures, provide a versatile platform for exploring light–matter interactions beyond conventional bulk materials. Owing to reduced dimensionality, enhanced quantum confinement, pronounced excitonic effects, and highly tunable electronic structures, these systems exhibit rich optical phenomena, including excitons, polaritons, plasmons, nonlinear optical responses, quantum emission, and moiré-engineered optical states.

This Collection aims to highlight recent advances in the optical properties and light–matter coupling mechanisms of low-dimensional quantum materials. Topics of interest include excitonic physics, infrared and terahertz optical responses, nonlinear optics, ultrafast carrier dynamics, polaritonic effects, and optical phenomena tunable by strain, twist, pressure, electric fields, or other external stimuli. We welcome both experimental and theoretical studies that reveal new physical mechanisms, develop advanced spectroscopic techniques, or demonstrate novel photonic and optoelectronic device concepts.

This Collection supports and amplifies research related to SDG 9.

Keywords: Low-dimensional Quantum Materials; Light–matter Interactions; Two-dimensional Materials; van der Waals Heterostructures; Quantum Dots; Excitons and Polaritons; Plasmonics; Moiré Materials; Terahertz Photonics; Nonlinear and Ultrafast Optics; Ultrafast Carrier Dynamics; Quantum Photonics

Moiré quantum matter has, in just a few years, become one of the most exciting and fast-moving areas of condensed-matter physics. When two atomically thin crystals are stacked with a small relative twist, or with a slight lattice mismatch, the resulting moiré superlattice produces electronic bands in which correlations, topology, magnetism, and superconductivity can all be tuned within a single device. What started with magic-angle twisted bilayer graphene now spans a whole family of platforms - twisted multilayers, graphene-on-boron-nitride superlattices, twisted and heterobilayer transition-metal dichalcogenides, twisted magnets, and twisted superconductors. This extraordinary tunability makes moiré systems not only a rich setting for fundamental questions but also a versatile toolbox for quantum devices: superconducting and Josephson architectures, valleytronic and spintronic elements, topological and Majorana-based platforms, single-photon detectors and quantum sensors, moiré-based quantum simulators, and hybrid quantum circuits.

We are looking for contributions across all of these directions - spanning materials growth and fabrication, transport, spectroscopy, optics, and device modelling, as well as the theory of correlations, topology, and non-equilibrium driving. This collection will bring together work ranging from the fundamental physics of moiré flat bands to concrete device concepts and emerging quantum technologies. We are aiming at original research on all aspects of moiré quantum matter and its application to quantum devices, while also welcoming reviews that cover relevant aspects of this topic.

Keywords: Moiré materials; moiré superlattices and flat bands; twisted bilayer graphene; twisted multilayer graphene; twisted transition-metal dichalcogenides; van der Waals heterostructures; superconductivity and band topology; Josephson junctions; valleytronics and spintronics; quantum transport