Interaction Between Laser andMaterials

The research on laser-matter interaction can bridge the gap between practical problems and
applications of lasers, which offers an important way to study material properties and to
understand intrinsic microstructure of materials. The laser irradiation-induced effects on
materials refer to numerous aspects, including optical, electromagnetic, thermodynamic,
biological changes in material properties. The laser-matter interaction is an interdisciplinary
and complicated subject [1]. When the material is irradiated with lasers, the laser energy will
be firstly transformed into electronic excitation energy and then transferred to lattices of
materials through collisions between electrons and lattices. The deposition of laser energy
will produce a series of effects, such as temperature rise, gasification and ionization. The
physical processes of interactions between lasers and matters can be grouped into linear and
nonlinear responses of materials to laser pulses, namely thermal effects, nonlinear
interactions, laser plasma effects and so forth [2,3]. This chapter aims at analyzing the abovementioned
major effects due to laser irradiation.
2. Thermodynamics
Laser ablation entails complex thermal processes influenced by different laser parameters,
inclusive of laser pulse energy, laser wavelength, power density, pulse duration, etc (Fig. 1).
According to the response of material to incident laser, the responses can be categorized into
two groups: thermal and mechanical effects. Thermal effects refer to melting, vaporization
(sublimation), boiling, and phase explosion while mechanical response involves
deformation and resultant stress in materials. Different thermal processes will induce
different mechanical responses, which will be detailed in the following