History, Scope, and the Future of Laser Ablation

Abstract

The study of the interaction of high-power lasers with solid matter is as old as the laser itself. Variously termed laser ablation, vaporization, sputtering, desorp-tion, spallation or etching, the physical processes involved are extremely complex. Electromagnetic energy is converted to electronic, thermal, chemical and mechanical energy at the solid surface. The ejected material may include neutral atoms and molecules, positive and negative ions, clusters, electrons and photons. The generated plasmas may have electron temperatures of thousands of degrees. Of necessity a multidisciplinary problem, the mechanism of laser ablation is still being studied and debated. Regardless of the detailed mechanisms, many important applications depend on laser ablation. These include industrial processes such as laser welding or hole drilling, materials! processing to produce thin films or microstructures, elemental analysis of solid samples, biomedical uses such as laser surgery or structural studies of biomolecules and, finally, laser-based weapons such as those discussed in the Star Wars Initiative. A subset of these applications areas is represented in this volume and the relevant physical mechanisms are discussed in detail in the following chapters. In the present chapter, the current status of laser ablation studies and applications will be put into a historical perspective and some future trends will be discussed.