Full-Continuum Ultrafast Quantum Gas Microscopy

Quantum gas microscopy provides single-shot access to many-body configurations, but their microscopic reconstruction has so far largely relied on a predefined discrete spatial basis during fluorescence readout. Here we realize ultrafast atom-resolved fluorescence microscopy of an ultracold ${}^{162}$Dy gas directly in continuous space, with all external confinement removed during imaging. Exploiting the large mass and broad optical transition of dysprosium together with a high numerical aperture in-vacuum objective, we detect single atoms within $4\mu \mathrm{s}$ while maintaining an effective point-spread function with a full width at half maximum of $254.8(3)\mathrm{n}\mathrm{m}$, and an isolated single-atom classification fidelity of $99.72(3)\mathrm{\%}$. We use the measured single-atom response to construct a statistical configuration-inference model that recovers atomic positions and multiplicities, coming from overlapping atoms, directly from single fluorescence snapshots. Benchmarking our model on Monte-Carlo generated images shows a total reconstruction fidelity of $98.7\mathrm{\%}$. Our approach extends quantum gas microscopy beyond predefined detection lattices, enabling atom-resolved measurements of counting statistics and higher-order spatial correlations directly on the intrinsic length scales of continuum many-body systems.