Spatially resolved photo ionization of ultracold atoms on an atom chip

TL;DR

This paper demonstrates spatially resolved photo ionization of ultracold Rb atoms on an atom chip, combining laser excitation and ionization to observe atomic depletion, with implications for BEC studies and single atom detection.

Contribution

It introduces a method for spatially resolved photo ionization of ultracold atoms on an atom chip, enabling detailed atomic state analysis and potential single atom detection.

Findings

Observed depletion of atomic density via absorption imaging

Reported resonant ionization spectrum of ultracold Rb atoms

Demonstrated setup suitable for BEC ion studies and single atom detection

Abstract

We report on photo ionization of ultracold magnetically trapped Rb atoms on an atom chip. The atoms are trapped at 5 $\mu $K in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 $\mu $m two laser beams are focussed onto a fraction of the atomic cloud. A first laser beam with a wavelength of 778 nm excites the atoms via a two photon transition to the 5D level. With a fiber laser at 1080 nm the excited atoms are photo ionized. Ionization leads to depletion of the atomic density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is not only suitable to investigate BEC ion mixtures but also single atom detection on an atom chip.