# Repeated Measurements with Minimally Destructive Partial-Transfer Absorption Imaging

## TL;DR

This paper introduces a minimally destructive imaging technique for ultracold atoms using partial-transfer absorption imaging, enabling multiple images of the same cloud with minimal perturbation, useful for dynamic measurements.

## Contribution

The authors develop and demonstrate a method for repeated imaging of ultracold atomic clouds with minimal disturbance using controlled microwave transfer to a bright state.

## Key findings

- Up to 50 images of the same atomic cloud can be obtained.
- The technique allows precise measurement of trap frequencies.
- Minimal perturbation preserves the atomic ensemble for multiple measurements.

## Abstract

We demonstrate partial-transfer absorption imaging as a technique for repeatedly imaging an ultracold atomic ensemble with minimal perturbation. We prepare an atomic cloud in a state that is dark to the imaging light. We then use a microwave pulse to coherently transfer a small fraction of the ensemble to a bright state, which we image using in situ absorption imaging. The amplitude or duration of the microwave pulse controls the fractional transfer from the dark to the bright state. For small transfer fractions, we can image the atomic cloud up to 50 times before it is depleted. As a sample application, we repeatedly image an atomic cloud oscillating in a dipole trap to measure the trap frequency.