Ion-Rydberg molecules observed by a high-resolution ion microscope*

Our ion microscope provides a highly tunable magnification, ranging from 200 to over 1500, a spatial resolution better than 200nm and a depth of field of more than 70µm. These properties and the excellent electric field compensation enable the observation of ion-Rydberg-interaction in cold bulk quantum gases [1].

The direct spatial imaging method allows for in-situ images of a new type of long-range Rydberg-atom-ion molecule in rubidium, which arises from a binding mechanism that is based on the interaction between the ionic charge and a flipping induced dipole of a Rydberg atom [2]. In our measurement scheme, we can image the two constituents (ions and Rydberg-atoms) in a distinguishable way, allowing us to obtain properties such as bond length or orientation of the molecule directly from our images.  In addition, the ion microscope also allows for spectroscopic studies of the vibrational level structure. Moreover, the good temporal resolution of the detector enables the observation of dynamic phenomena during the interaction process which compared to traditional molecules are slowed down by many orders of magnitude.

[1] Veit, C., et al. "Pulsed ion microscope to probe quantum gases." Physical Review X 11.1 (2021): 011036.

[2] Zuber, N., et al. "Spatial imaging of a novel type of molecular ions." arXiv preprint arXiv:2111.02680 (2021).