Precision Measurement of the Cs 5D_5/2 and 5D_3/2 Excited State Lifetime Using a Single Atom in an Optical Tweezer

In cesium, high-lying 5D states are central to tests of many-body atomic theory and to building reliable single-atom platforms, yet historical lifetime measurements show substantial inconsistencies with theoretical determined values. Single-atom optical tweezers provide a powerful route to precision spectroscopy and metrology by eliminating ensemble effects such as radiation trapping and collisional quenching. Motivated by resolving these discrepancies with a systematics-clean approach, we trap a single ¹³³Cs atom in a 1064-nm tweezer and excite 6S₁/₂ → 5D₅/₂ on the 685-nm electric-quadrupole transition. We extract the lifetime from time-tagged 852-nm cascade fluorescence using a convolution fit that accounts for the measured excitation turn-off. Aggregating ~10⁹ repetitions across runs, we establish a precision single-atom lifetime measurement platform for Cs 5D states. In parallel, we also demonstrate single-atom driving of the Cs 5D₃/₂ manifold, which lacks a closed optical cycling transition, and measure the optical frequencies of the hyperfine components (F=2,3,5). Looking ahead, we will integrate these capabilities with time-correlated single-photon counting (TCSPC) to perform the first single-atom lifetime measurement of 5D₃/₂ using similar methodology, and further characterize the change of those lifetimes in presence of external perturbations.