Product Description
This book aims to be a presentation of the basic chemical and physical processes induced by laser irradiation on solid surfaces.The advent of high-power laser systems was accompanied by the emergence of laser metal processing as their chief application. This book discusses the heating of metals by laser beams at intensity levels too low, or radiation times too short, to cause target material ablation and plasma formation near the metal surface. The specificity of this approach to the topic rests with the factors governing heating kinetics under the above mentioned conditions. Among these are the thermophysical properties of metals, the optical properties of the metal and target surface, the beam and target sizes, the distribution in space of the laser beam and its temporal-spatial intensity, polarization and the angle of incidence, the composition of the surrounding gas and its pressure. Simple and convenient formulae are given for calculating the evolution in space and time of the temperature distribution in metal targets for the most common irradiation conditions and target geometries. The temperature variation of the optical and thermophysical properties of the target material, including its transition through the melting point, are given particular emphasis. Attention is paid to radiation-induced reversible and irreversible thermodeformations and their contribution, as well as that of metal melting and vapourization, in the optical damage of laser mirrors. Two classes of laser-induced surface phenomena are discussed, which play a part in the heating rate of the metal target, namely the interaction of the laser beam with self-induced, or pre-existing, resonant and non-resonant surface structures and processes of thermochemical origin.
