Stronger than atoms

A new generation of small, relatively cheap lasers, capable of producing previously unattainable intensities, has been produced. The light beams they generate are physically stronger than the internal forces in ordinary matter thus offering many new research possibilities described here. These ''strong'' laser beams take over from the internal atomic field in controlling the behaviour of electrons in matter even after they have become ''free''. Thus the matter becomes something like a plasma consisting of ions and free electrons. This research field has drawn ideas together from laser, plasma and atomic physics. Fresh insights are emerging about how light interacts with matter, when light is the stronger partner. New applications well outside the boundaries of laser and plasma physics are anticipated. (UK)