Cavity quantum electrodynamics with moiré photonic crystal nanocavity.

Due to the existence of flatbands within the band structure, twisting photonics introduces a possibility to enhance the interaction between excitons in single QDs and cavity photons because of the extremely high quality factor (Q) in theory. In this work, we report a Purcell effect between single QDs and moiré photonic crystal nanocavities. The moiré photonic crystal nanocavities in a GaAs slab with QDs embedded are formed by twisting two layer photonic crystal structures with specific angles. High Q, low mode volume and large overlap between QDs and cavity mode field have been achieved by optimizing the filling ratio of the single-layer photonic crystal, with which a Q of fundamental modes about 2000 is experimentally demonstrated. A photoluminescence intensity enhancement of a factor about 8.4 is observed when a single QD is in resonance with a cavity mode, with a Purcell factor of about 3.0 confirmed through the lifetime measurement. This result shows the potential of moiré photonics to implement solid-state cavity quantum electrodynamics for future optical quantum information processing.