Selective excitation and trajectory control of flying rydberg sodium atoms

We demonstrate the selective excitation and detection of a free-flying Rydberg sodium atom possessing a giant induced electric dipole moment. By applying a tunable external electric field, we develop a method to generate and precisely control large permanent dipole moments through strong in-flight polarization. The magnitude and sign of the resulting dipole moment are determined by the internally excited quantum state of the atom, which is selectively prepared via resonant laser excitation. In an inhomogeneous electric field, the state-dependent force proportional to the dipole moment, enables direct manipulation of the atomic trajectory. We introduce a dipole separation stage that resolves the atomic quantum state through time-of-flight (TOF) measurements. This design can be cascaded to amplify TOF differences, allowing for clear quantum state discrimination. Using a multi-stage electric accelerator/decelerator setup, we successfully realize this approach with sodium atoms. Our work highlights the selective excitation and detection of metallic Rydberg atoms in flight and introduces a movable electric trap design for precise trajectory control, showcasing the potential of flying gradient electric fields for quantum-state-selective manipulation and detection.