Electron excitation in glasses and sapphire followed by time- and space-measuring tools

Temporal and spatial changes in the matrix of glasses (BK7 glass, fused silica, quartz) and sapphire are investigated during and after irradiation by pulsed laser radiation (100 fs < t(ind p) < 3 ps) at the wavelength lambda = 800 nm using high-speed photography, transient absorption spectroscopy, and Nomarski-microscopy in order to visualize the changes of optical properties, the plasma formation and expansion, the stress formation, the modification, and the cracking as well. Depending on the excitation conditions the glasses and sapphire exhibit different excitation and relaxation channels including various types of defect centers. Compared to laser radiation with pulse durations in the nanosecond regime the glasses and sapphire are heated within the irradiation zone for many nanoseconds resulting in modification by an increase of the refractive index without cracking, enabling the generation of photonic structures within the bulk. Irradiation at pulse durations in the picosecond regime originates in cracking enabling the marking and microstructuring in the bulk and at the surface.