Dielectric microlasers: From periodic to aperiodic

Laser miniaturization represents an important direction in laser science and technology, offering reduced power consumption, improved energy efficiency, and increased integration density. Enabled by advances in semiconductor materials and fabrication technologies, dielectric micro- and nanostructures have attracted increasing attention as versatile platforms for functional microlaser devices. Represented by photonic crystal lasers, periodic dielectric structures provide powerful mechanisms for engineering optical feedback through photonic band structures, including band edge feedback and bandgap-confined defect modes. In recent years, the introduction of photonic band topology, optical bound states in the continuum (BICs), relaxed lattice symmetry, and precise local structural modulation have further expanded dielectric microlasers from periodic lattice designs toward aperiodic and locally engineered architectures. These emerging principles provide additional mechanisms for radiation control, leading to improved lasing performance and enriched emission functionalities. In this review, we summarize recent progress in dielectric microlasers, covering BIC and quasi-BIC microlasers, topologically protected defect- and edge-mode lasers, moiré superlattice and quasicrystal lasers, and locally modulated microlaser platforms. Together, these advances highlight the evolution of dielectric microlasers from periodic lattice designs to aperiodic structures with expanded degrees of freedom, establishing them as promising integrated coherent sources for multifunctional photonic systems. Finally, we compare the key advantages and limitations of different microlaser platforms, highlight their recent advances, and discuss future opportunities for practical device implementation, including structured-light generation, active tunability, gain-material development, and scalable fabrication.