Minimally-destructive Partial Phase Contrast Imaging

This paper presents a minimally-destructive imaging technique based on a combination of phase contrast and Faraday rotation imaging used to continuously observe a condensate of 85 Rb. We demonstrate that the technique is capable of imaging a small sample of only 10 4 atoms up to 100 times with negligible decreases in atom number and no observable heating. At approximately 1GHz detuning, the SNR remains at approximately 7 for all 100 images, with a 22ms TOF absorption image confirming the survival of the condensate. The splitting of the magnetic sublevels of this species at such fields show non-trivial selection rules. We present experimental data outlining particular allowed transitions in this regime.