Emission enhanced exciton-polariton condensates with optical feedback

Optical feedback is a well-known method of controlling laser dynamics, which has been widely studied in photonic systems to induce complex behaviors such as chaos or enhanced coherence. However, its application to systems in the strong light-matter coupling regime remains unexplored. In this work, we introduce a delayed optical feedback loop into a nonresonantly pumped polariton condensate. By feeding part of the emission back into the cavity to seed the next condensate, we observe a strong increase in the output intensity, up to 110%. We explain this effect using a classical rate equation model for the condensate coupled to excitonic reservoirs. Our results evidence that polariton condensates can respond strongly to optical feedback, congruent with well known polariton amplification techniques using resonant pump-probe setups. Our method opens new possibilities for using polariton feedback to connect multiple condensates and can be an essential step toward neuromorphic computing based on recurrent signaling in photonic systems.