Coupled microbeads for unidirectional cascade lasing transfer

•First experimental demonstration of a coupled-cavity down-conversion microlaser device.•New development of a simple rate model to predict behavior of coupled cavity fluorescent or lasing devices.•Experiment and theory are linked so that future developments can be designed and predicted.•The first two points above represent novelty. The work isn’t just an incremental advance over previous published results, because there are no previous published results on this model approach or this precise experimental design.