High-speed observation of stress wave propagation and damage generation during ultrashort pulse laser drilling of sapphire

Abstract

We used a combination of pump-probe imaging method and high-speed camera to visualize the damage generation process in sapphire during ultrashort pulse laser processing. As a result, we found that the damage was generated by stress waves propagating through the material, and that the mode of stress wave generation changed as the number of irradiation pulses increased. The mechanism of damage generation during processing observed in this study will contribute to the development of precision processing methods for sapphire.