2026 Theses Doctoral

Strontium Tweezer Arrays via Holographic Metasurfaces

Holman, Aaron

Optical tweezer arrays have emerged as a key experimental platform for quantum computation, quantum simulation, and quantum metrology, enabling a bottom-up approach to assembling and studying quantum systems. Realizing the full potential of these systems, however, requires advances across the entire experimental stack: simpler sources of cold atoms, scalable optical tools for trapping and control, and new avenues for exploring many-body quantum phenomena. This thesis describes the development of an experimental platform for studying single strontium atoms in optical tweezer arrays generated by holographic metasurfaces, and the progress toward studies of the strontium 2.9 μm transition and the collective optical behavior of ordered atomic arrays.

The first part of this thesis outlines the construction of the apparatus. In particular, the development of a compact strontium source based on a dispenser-loaded two-dimensional magneto-optical trap is described. In contrast to more typical oven-based architectures, this approach is designed to reduce the size, complexity, and power consumption of the atomic source. We characterize its performance through the loading of a downstream three-dimensional magneto-optical trap and demonstrate atomic flux comparable to conventional strontium sources. By simplifying the production of cold strontium, this work helps lower a practical barrier to the broader adoption and proliferation of strontium-based atomic platforms.

The second part of this thesis concerns the generation of optical tweezer arrays using holographic metasurfaces. Conventional beam-shaping approaches impose constraints on the scalability of optical tweezer arrays. Holographic metasurfaces offer a fundamentally different route: these subwavelength-structured optical chips both shape and focus light, all within a single CMOS compatible device. We demonstrate the first trapping and control of single atoms in metasurfacegenerated arrays, and further highlight the extreme scalability of this approach through the realization of a 360,000-tweezer array. This work establishes metasurfaces as a scalable optical architecture for neutral-atom experiments, and eventually, technologies.

The final part of this thesis leverages this platform for the mid-infrared control of strontium on the 2.9 μm transition. Long-wavelength transitions remain relatively unexplored in atomic experiments, but they offer a promising route to studies of collective light-matter phenomena. We demonstrate the key ingredients needed to access this physics, including single-atom preparation and imaging at a new trapping wavelength, confirmation of a magic trapping condition for the 2.9 μm transition, and, to our knowledge, the first sideband cooling of an atom in a metastable state. This work opens a path toward subwavelength atomic arrays and future studies of collective emission, including superradiant and subradiant many-body states.