We develop an ultracompact high-resolution imaging system for cold atoms. Its only in-vacuum element is a multimode optical fiber with a diameter of 230 $\mu \mathrm{m}$, which simultaneously collects light and guides it out of the vacuum chamber. External adaptive optics allow us to image cold $\mathrm{Rb}$ atoms with approximately 1-$\mu \mathrm{m}$ resolution over a $100\times 100\mu {\mathrm{m}}^2$ field of view. These optics can be easily rearranged to switch between fast absorption imaging and high-sensitivity fluorescence imaging. This system is particularly suited for hybrid quantum-engineering platforms where cold atoms are combined with optical cavities, superconducting circuits, or optomechanical devices restricting optical access.

• Received 18 December 2020
• Revised 29 April 2021
• Accepted 2 June 2021

DOI:https://doi.org/10.1103/PhysRevApplied.15.064047