A half-cavity design for improved readout of atoms and remote entanglement in an optical tweezer array

Scalable quantum simulators and computers composed of stationary neutral atom qubits have emerged as leading experimental platforms for quantum science. These systems would benefit from higher fidelity state preparation and measurement (SPAM) and from flexible methods for efficient remote entanglement distribution via photons. To advance both of these goals, we propose a "half-cavity" architecture that integrates reflective optics and two precisely aligned high NA lenses in a neutral-atom optical tweezer-array quantum simulator. The half-cavity operates by combining the standard collection of fluorescence through one high-NA lens with fluorescence collected and reflected back through a second high-NA lens. We use an interferometric technique to obtain the required alignment of the two high-NA lenses. We present three different half-cavity designs which enable different experimental capabilities: The first configuration improves the single photon-collection efficiency of the apparatus above the NA of a single lens, while the other two configurations are designed to implement photon-mediated entanglement between distant arrays of atoms in parallel via which-way information erasure. We calculate the stability of the half-cavity using generalized ray transfer matrix analysis and analyze the expected optical performance of the half-cavity through numerical vectorial diffraction simulations. We investigate the potential to use a spatial light modulator (SLM) in the third half-cavity configuration to create an entangled atom cluster within a single detection by superimposing the images of multiple atoms onto one atom.