Disorder Suppression via a Pulsed Laser in an Erbium Quantum Gas Microscope

Quantum gas microscopes provide site-resolved control and detection of ultracold atoms in optical lattices, enabling the direct study of strongly correlated quantum matter. However, a fundamental challenge of optical lattice experiments is the need to craft ultra-low-disorder optical potentials. One prominent source of lattice disorder in continuous-wave lattices arises from stray light interfering with the main lattice beams. Enhanced by the large field amplitude of the primary lattice, even minuscule amounts of stray light from dust scattering or higher-order optical reflections can produce significant disorder.

Here, we propose a solution utilizing a lattice generated by a pulsed laser, which efficiently suppresses the interference-induced disorder. The laser's short coherence length allows us to circumvent interference from stray beams and create an lattice constructed from the overlap of two time-delayed laser pulses, with a pulse delay engineered to center the lattice in the atom plane. Stray beams acquire an optical path length difference exceeding the coherence length of the light and do not interfere in the atom–lattice plane. This technique strongly suppresses interference-induced lattice disorder, allowing us to reach a residual Hz-level RMS in lattice depth variations. With its relative simplicity, this configuration can be easily implemented into experiments suffering from disorder and paves the way for future ultra-low-disorder quantum systems.