Interaction of ultrashort laser pulses with transparent materials is a powerful technique of modification of material properties for various technological applications. The physics behind laser-induced modification phenomenon is rich and still far from complete understanding. We present an overview of our models developed to describe processes induced by ultrashort laser pulses inside and on the surface of bulk glass. The most sophisticated model consists of two parts. The first part solves Maxwell’s equations supplemented by the rate and hydrodynamics equations for free electrons. The model resolves spatiotemporal dynamics of free-electron population and yields the absorbed energy map. The latter serves as an initial condition for thermoelastoplastic simulations of material redistribution. The simulations performed for a wide range of irradiation conditions have allowed to clarify timescales at which modification occurs after single laser pulses. Simulations of spectrum of laser light scattered by laser-generated plasma revealed considerable blueshifting which increases with pulse energy. To gain insight into temperature evolution of a glass material under the surface irradiation conditions, we employ a model based on the rate equation describing free electron generation coupled with the energy equations for electrons and lattice. Swift heating of electron and lattice subsystems to extremely high temperatures at fs timescale has been found at laser fluences exceeding the threshold fluence by 2-3 times that can result in efficient bremsstrahlung emission from the irradiation spot. The mechanisms of glass ablation with ultrashort laser pulses are discussed by comparing with the experimental data. Finally, a model is outlined, developed for multi-pulse irradiation regimes, which enables gaining insight into the roles of defects and heat accumulation.
In materials engineering, we are often faced with a necessity to display the shape and morphology of studied surfaces.
This is essential for surface evaluation of various components as well as for new materials research. Several imaging
techniques are available for such purposes. One of the most appropriate of them is laser scanning confocal microscopy.
The magnification range of this technique satisfies the needs of researchers working between the limits of conventional
optical microscopes and scanning electron microscopes. It overcomes the limitations of optical microscopy by better
lateral resolution, ability to control the depth of field and possibility of high-resolution 3D imaging of relatively thick
samples. Compared to the more advanced (and more expensive) scanning electron microscopes, laser scanning confocal
microscopy has no special requirement for the sample preparation and there is also no need to measure in vacuum.
Particular examples of laser scanning confocal microscopy beneficial use are presented in this paper. Scratch track
evaluation, diamonds tip control, Tyvek structure examination and measurement of surface characteristics of a wire saw
cut on the glass are reported.