Resonance enhanced ionisation spectroscopy on laser-cooled rubidium atoms

We report the utilization of resonance-enhanced ionization to perform high-resolution spectroscopy on laser-cooled atoms. The technique is applied to the 5S1/2- 5P3/2 - 5DJ (J = 3/2 , 5/2 ) optical double resonances of rubidium atoms in a magneto-optical trap. Ions generated when atoms in the double excited state absorb a single photon are detected, together with the induced fluorescence. The two detection channels are compared for this class of high-resolution spectroscopy experiment.