Laser-Beam Interactions with Materials

Lasers, having proven useful in such diverse areas as high- resolution spectroscopy and the guiding of ferryboats, are cur- rently enjoying great popularity among materials scientists and engineers. As versatile sources of "e;pure"e; energy in a highly concentrated form, lasers have become attractive tools and re- search instruments in metallurgy, semiconductor technology and engineering. This text treats, from a physicist's point of view, some of the processes that lasers can induce in materials. The field of laser-material interactions is inherently mul- tidisciplinary. Upon impact of a laser beam on a material, electromagnetic energy is converted first into electronic exci- tation and then into thermal, chemical and mechanical energy. In the whole process the molecular structure as well as the shape of the material are changed in various ways. Understand- ing this sequence of events requires knowledge from several branches of physics. A unified presentation of the subject, for the benefit of the materials researcher as well as the advanced student, is attempted here. In order to keep the book reason- ably trim, I have focused on laser effects in solids such as thin films and technological materials. Related topiCS not cov- ered are laser-induced chemical reactions in gases and liquids and laser effects in organic or biological materials.