Mesoscale engineering of photonic glass for tunable luminescence

Control of the optical behavior of active materials through manipulation of their microstructure has led to the development of high-performance photonic devices with enhanced integration density, improved quantum efficiencies and controllable color output. However, the achievement of robust light-harvesting materials with tunable, broadband and flattened emission remains a long-standing goal owing to the limited inhomogeneous broadening in ordinary hosts. Here, we describe an effective strategy for the management of photon emission by manipulating the mesoscale heterogeneities in optically active materials. Importantly, this unique approach enables control of dopant-dopant and dopant-host interactions on the extended mesoscale. This allows the generation of intriguing optical phenomena such as a high activation ratio of the dopant (close to 100%), dramatically inhomogeneous broadening (up to 480 nm), notable emission enhancement and, moreover, simultaneously extension of the emission bandwidth and flattening of the spectral shape in glass and fiber. Our results highlight that the findings connect the understanding of and manipulation in the mesoscale realm to functional behavior on the macroscale, and the approach to manage the dopants based on mesoscale engineering may provide new opportunities for the construction of a robust fiber light source.