Focus and depth of field tunable detection system for compact quantum sensors

Absorption imaging is a well-established method for determining both the atom number and spatial distribution of atomic ensembles, traditionally limited to a single focal plane and a fixed depth of field. However, as atom optics experiments grow more complex, atomic clouds can exceed the depth of field or leave the focal plane, as seen in large atomic arrays or bubble Bose-Einstein condensates (BECs). Here, we present an absorption imaging system that allows for tuning the object distance of 88.9 mm by ±5 mm and the depth of field from 26 µm to 203 µm. We determine performance metrics relevant for atomic experiments, such as the resolution and the optical distortion.