Lasing from ordered colloidal micro-resonator arrays to random distributed systems

Abstract

While colloidal microstructures are widely utilized to engineer ordered micro-resonator arrays with precise optical responses, intentionally harnessing their inherent structural randomness opens new ways for tailoring light–matter interactions. In this study, we investigate the profound impact of programmable structural disorder on the light-scattering and emission properties of colloidal micro-assemblies. Focusing on a dye-doped polymer system incorporating hollow silica microspheres, we demonstrate how controlled stochasticity alignment modulates the dominant optical feedback mechanisms. By manipulating surface tension-driven self-assembly, we observe a continuous morphological evolution from locally ordered, two-dimensional micro-gratings arrays to highly scattering macro-aggregates. Crucially, we show that increasing this structural disorder alters the light amplification pathway, transforming the optical emission sequentially, from distinct, localized resonant modes within well-defined cavities, through non-resonant amplified spontaneous emission (ASE), and ultimately culminating in robust random lasing (RL). Our findings underscore that integrating self-assembly principles with deterministically controlled randomness provides a powerful strategy to precisely engineer the emission regimes of photonic materials.