Interaction of shock electromagnetic waves with transparent materials: classical approach

There is discussed a theoretical model of initiating of laser-induced damage and ablation of transparent materials by femtosecond pulses based on properties of shock electromagnetic wave (SHEW). Advantages of this model are increased efficiency of SHEW-induced ionization and possibility of effective straight action of SHEW front on ions at crystal-lattice points. It is presented simplified description of SHEW-induced processes within approach of classical mechanics and electrodynamics: atoms are described as dipoles with certain ionization energy interacting with SHEW in potential well formed by crystal lattice. There are considered possibilities of laser-induced ionization by higher harmonics appearing during SHEW formation and point-defect formation and delocalization of ions at crystal points by SHEW. Obtained results and predictions are compared with experimental data and shown to be capable of explaining many observed regulations of femtosecond laser interactions with transparent media.