Crack growth analysis of ultraviolet nanosecond laser scanning glass with acoustic emission.

Undesirable crossing crack defects are prone to occur in the laser processing of glass, but a comprehensive analysis of the crack mechanism is absent. We apply an acoustic emission (AE) monitoring technique in the glass's laser scanning to reveal the crack phenomenon. A two-step experiment (single-line and multi-line scanning) is designed to present the crossing crack's occurrence and growth, and the corresponding AE signals are collected and analyzed in different domains.

Temperature Field-Assisted Ultraviolet Nanosecond Pulse Laser Processing of Polyethylene Terephthalate (PET) Film.

Understanding the mechanism of and how to improve the laser processing of polymer films have been important issues since the advent of the procedure. Due to the important role of a photothermal mechanism in the laser ablation of polymer films, especially in transparent polymer films, it is both important and effective to adjust the evolution of heat and temperature in time and space during laser processing by simply adjusting the ambient environment so as to improve and understand the mechanism of this procedure. In this work, studies on the pyrolysis of PET film and on temperature field-assisted ultraviolet nanosecond (UV-ns) pulse laser processing of polyethylene terephthalate (PET) film were performed to investigate the photothermal ablation mechanism and the effects of temperature on laser processing.