Microcavity Complex Lasers: from Order to Disorder

Microstructures, characterized by gain, nonlinearity, internal scattering, and boundary effects, offer an exceptional platform for exploring complex optical phenomena such as random lasing, chaos, and multidimensional speckles. Specifically, complex lasers generated within microcavities and optical fibers, where strong light confinement and scattering play diverse roles, have become a significant branch of laser research. Recently, the rapid advancement of materials, micro-nano technologies, and artificial intelligence has introduced new opportunities and challenges for the generation, control, and application of complex lasers. This review systematically examines various types of microcavity complex lasers from the perspective of microcavity structures with different degrees of disorder. It primarily focuses on the historical development, characteristics, regulation, and applications of disordered microcavity lasers and concludes with a discussion on the future trends in the development of microcavity complex lasers.