Ultrafast Machining through Heating Laser-Excited Electrons
摘要
Abstract
Although the precision ablation of transparent hard and brittle materials using ultrashort pulse lasers has been widely investigated
the speed of material removal remains low. In this study
we achieved ultrafast and precise material removal by creating a long-lifetime plasma filament inside the material and sufficiently heating it. A crack-free microhole with a depth of approximately 60 μm and a diameter of approximately 4 μm was generated within 2 μs. The machining speed was 4.3 × 10 times faster than conventional femtosecond laser processing. The dynamics of the plasma filament induced by an ultrashort pulse laser were investigated using the pump-probe method
indicating a slow decay of excited electrons owing to their high density. Through experiments and simulations
we revealed that a microsecond laser pulse can more effectively heat the plasma filament for material removal because of higher energy absorption. Moreover
the timing between filament generation and laser heating plays a critical role in machining due to the relaxation of excited electrons. This work provides an attractive route for advanced precision fabrication in industrial applications
as well as for facilitating the understanding of laser–matter interactions.