The narrow slit of the micro ion trap allows for an optical cavity with high coupling  such that the strong coupling regime is reached.  For cavity QED experiments with conventional ion traps see the work at Innsbruck, at Univ. of Sussex and in the Chapman group. We intend to use fibre optical cavities as established in the Hänsch group in Munich and Reichel group at ENS, Paris. 
This work is supported by the european network SCALA.