Experiment set-up (IMAGE) Macquarie University Caption (Top) Schematic of the setup used for the quantum-cascade experiment by Scarpelli et al, and (bottom) illustration of the three-exciton bound state coupled to the light-matter particles in the fibre cavity. The bound state changes the interactions between the light-matter particles and strongly modifies the properties of the emitted light. Credit L. Scarpelli and M. Richard Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.