Switching a monolayer atomic mirror using a single Rydberg atom*

Understanding and tuning light-matter interactions is essential for numerous applications in quantum science. Cooperative response between light-coupled atoms has recently led to the realization of a sub-radiant mirror formed by an atomic monolayer with strong light-matter coupling even down to the level of single photons^[1]. Here, we control the optical response of such an atomic mirror using a single ancilla atom excited to a Rydberg state. The switching behavior is controlled by admixing Rydberg character to the atomic mirror and exploiting strong dipolar Rydberg interactions with the ancilla. Driving Rabi oscillations on the ancilla atom, we demonstrate coherent control the degree of transmission and reflection. Finally, increasing the mirror size directly reveals the spatial area around the ancilla atom where the switching is effective. Our results pave the way towards novel quantum metasurfaces and the creation of controlled atom-photon entanglement.

[1] J. Rui et. al, Nature 583, 369–374 (2020).