Single Sr Atoms in Optical Tweezer Arrays for Quantum Simulation

We report on the realization of a platform for trapping and manipulating individual 88Sr atoms in optical tweezers. A first cooling stage based on a blue shielded magneto-optical trap (MOT) operating on the (Formula presented.) transition at (Formula presented.) enables us to trap approximately 4 × 106 atoms at a temperature of 6.8 mK. Further cooling is achieved in a narrow-line red MOT using the (Formula presented.) intercombination transition at 689 nm, bringing 5 × 105 atoms down to (Formula presented.) and reaching a density of 4 × 1010 cm3. Atoms are then loaded into 813 nm tweezer arrays generated by crossed acousto-optic deflectors and tightly focused onto the atoms with a high-numerical-aperture objective. Through light-assisted collision processes we achieve the collisional blockade, which leads to single-atom occupancy with a probability of about 50%. The trapped atoms are detected via fluorescence imaging with a fidelity of (Formula presented.), while maintaining a survival probability of (Formula presented.). The release-and-recapture measurement provides a temperature of (Formula presented.) for the atoms in the tweezers, and the ultra-high-vacuum environment ensures a vacuum lifetime higher than 7 min. These results demonstrate a robust alkaline-earth tweezer platform that combines efficient loading, cooling, and high-fidelity detection, providing the essential building blocks for scalable quantum simulation and quantum information processing with Sr atoms.