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We propose metasurface holograms as a novel platform to generate optical trap arrays for cold atoms with high fidelity, efficiency, and thermal stability. We developed design and fabrication methodologies to create dielectric, phase-only metasurface holograms based on titanium dioxide. We experimentally demonstrated optical trap arrays of various geometries, including periodic and aperiodic configurations with dimensions ranging from 1D to 3D and the number of trap sites up to a few hundred. We characterized the performance of the holographic metasurfaces in terms of the positioning accuracy, size and intensity uniformity of the generated traps, and power handling capability of the dielectric metasurfaces. Our proposed platform has great potential for enabling fundamental studies of quantum many-body physics, and quantum simulation and computation tasks. The compact form factor, passive nature, good power handling capability, and scalability of generating high-quality, large-scale arrays also make the metasurface platform uniquely suitable for realizing field-deployable devices and systems based on cold atoms.

We present a continuous, narrow-linewidth, tunable laser system that outputs up to 14.0 W at 770 nm. The light is generated by frequency doubling 18.8 W of light from a 1540 nm fiber amplifier that is seeded by a single-mode diode laser achieving$><\#comment/>74\mathrm{\%<\#comment/>}$conversion efficiency. We utilize a lithium triborate crystal in an enhancement ring cavity. The low intensity noise and narrow linewidth of the 770 nm output are suitable for cold atom experiments.

Ensemble qubits with strong coupling to photons and resilience against single atom loss are promising candidates for building quantum networks. We report on progress towards high fidelity preparation and control of ensemble qubits using Rydberg blockade. Our previous demonstration of ensemble qubit preparation at a fidelity <60% was possibly limited by Rydberg blockade leakage due to uncontrolled short range atom pair separation. We show progress towards ensembles with a blue-detuned 1-D lattice on top of the existing red-detuned dipole trap, which will suppress unwanted Rydberg interactions by imposing constraints on the atomic separation. We study the effect of lattice insertion on the fidelity of ensemble state preparation and Rydberg-mediated gates. Studies of cooperative scattering from a 1D atomic array will also be presented.