Integrated, Ultrafast All-Optical Transistors and Gates with Organic Exciton-Polariton Condensates

Ultrafast all-optical circuits have the potential to perform logic operations orders of magnitude faster than electronics. In particular, using polymer in a microcavity in strong light-matter interaction regime has allowed to realize transistor action and Boolean logic on a picosecond time scale by exploiting seeded polariton condensation at room temperature. However, the vertical cavity geometry, the work horse of polaritonics in the past decades, is a challenge for more complex, integrated circuits. Using high-index contrast grating cavities filled with an organic pi-conjugated polymer, we create exciton-polariton condensates on a chip. With a footprint of 2 × 2 µm2, the resonators are extremely compact, and the light can be guided between devices through the polymer layer. Coupling two resonators where one generates the signal and the other serves as transistor, we demonstrate ultrafast switching within less than 2 ps and achieve up to 60X amplification and 8:1 extinction ratio. Furthermore, we realize AND/OR functionality by coupling multiple cavities. Using a sequence of three excitation pulses, we validate the cascadability of the devices. Moreover, we investigate larger, linear arrays of microcavities. Coupling up to 14 resonators that are excited synchronously, we observe coherent coupling between the resonators, generating delocalized states over the whole array. These experiments set the foundation for a new generation of integrated polaritonic circuits.