Chiral‐Plasmon‐Tuned Potentials for Atom Trapping at the Nanoscale

Abstract Neutral atom trapping is of importance in precision quantum metrology and quantum information processing where the atom can be viewed as an excellent frequency reference. However, creating tunable optical traps compatible with the optical nanostructures is still a challenge. Here, by introducing the chiroptical effects of a plasmonic structure into atom trapping, an active tunable potential for 3D stable optical trapping at the nanoscale is demonstrated. By altering the incident light from left‐ to right‐handed circularly polarized, the tunable range of position and potential of the trapped atoms can reach ≈60 nm and ≈0.51N mK (N denotes input power with unit mW), respectively. In addition, the blue‐detuned circularly polarized light guarantees the ultralow scattering rate and ultralong trapping lifetime. The trap centers are about hundreds of nanometers away from the structure surface, which ensures the stability of the trapping system due to the ignorable surface potential. This chiral‐based tunable atom trapping system broadens the application of chiral metamaterials and has important impact on all‐optical modulation, atomic on‐chip integration, manipulation of cold atoms, and quantum many‐body systems.