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

Kagome materials, characterized by networks of corner-sharing triangles, provide a versatile platform for exploring emergent quantum phenomena arising from the interplay of lattice geometry, topology, electron correlations, and magnetism. Their distinctive electronic structure supports flat bands, Dirac dispersions, van Hove singularities, and strong magnetic frustration, making them an ideal setting for unconventional electronic and spin states. Recent discoveries in kagome metals, magnets, and superconductors have revealed a rich variety of ordered phases, including charge density waves, superconductivity, nematicity, magnetism, chiral electronic orders, and possible time-reversal symmetry breaking states.

A central challenge in this field is understanding how these competing and coexisting orders interact and evolve under external tuning. In many kagome systems, multiple competing instabilities emerge in close energetic proximity, indicating that their quantum phases are inherently intertwined rather than independent. The ability to tune these phases through chemical substitution, pressure, strain, magnetic field, reduced dimensionality, gating, and heterostructure engineering further opens new opportunities to manipulate correlated and topological states in a controlled manner.

This Collection aims to highlight recent progress on intertwined orders and tunable quantum phases in kagome materials. We welcome experimental, theoretical, and computational contributions on material discovery, microscopic mechanisms, and phase control, with emphasis on emergent ordering phenomena, phase competition and coexistence, and the external tuning of quantum states in kagome systems.

This Collection supports and amplifies research related to SDG 9.

Keywords: Kagome Materials; Intertwined Orders; Tunable Quantum Phases; Unconventional Superconductivity; Charge Density Waves; Quantum Materials; Correlated Electron Systems; Topological Materials