Multi-state detection and spatial addressing in a microscope for ultracold molecules

TL;DR

This paper demonstrates in-situ detection and spatial addressing of individual ultracold molecules in a lattice, enabling precise measurements of density, internal states, and local control.

Contribution

It extends atomic quantum gas microscopy techniques to molecules, allowing simultaneous detection of position and internal states with spatial resolution.

Findings

Achieved detection of individual molecules with sub-micron resolution.

Mapped two internal states to different atomic species for simultaneous detection.

Implemented local addressing using focused light to control molecular states.

Abstract

Precise measurement of the particle number, spatial distribution and internal state is fundamental to all proposed experiments with ultracold molecules both in bulk gases and optical lattices. Here, we demonstrate in-situ detection of individual molecules in a bulk sample of 87Rb133Cs molecules. Extending techniques from atomic quantum gas microscopy, we pin the molecules in a deep two-dimensional optical lattice and, following dissociation, collect fluorescence from the constituent atoms using a high-numerical-aperture objective. This enables detection of individual molecules up to the resolution of the sub-micron lattice spacing. Our approach provides direct access to the density distribution of small samples of molecules, allowing us to obtain precise measurements of density-dependent collisional losses. Further, by mapping two internal states of the molecule to different atomic species, we demonstrate simultaneous detection of the position and rotational state of individual molecules. Finally, we implement local addressing of the sample using a focused beam to induce a spatially-dependent light shift on the rotational transitions of the molecules.