Laser excitation of ion beams

During the last decade laser excitation of fast ion beams has become a powerful tool in atomic and molecular spectroscopy. The high velocity of the ions makes it possible to perform accurate lifetime measurements of excited states in a geometry with crossed ion and laser beams. The selective laser excitation avoids the problem of cascades from upper levels. Recent lifetime measurements of singly ionized atoms performed in our laboratory are discussed, as well as other possible uses of the high time resolution in crossed beam experiments. Very high spectral resolution (sub-Doppler) measurements of hyperfine structure and isotope shifts with collinear laser and ion beams are also reviewed.