Abstract
In this paper recent experiments with the one-atom maser or micromaser performed by our group will be reviewed, as well as experiments with single ions in traps. The discussion is limited to results relevant in connection with the experimental realization of a quantum computer. The principle of the electrode configuration of the ion trap used for the investigation of the spectrum of resonance fluorescence described in the second part of this paper has also been used to realize a linear trap. This work on resonance fluorescence and the more recent work on ordered structures in a miniature trap being produced recently are the basis for the use of such a set-up for quantum computers.