Ultrafast laser processing of ceramics: Comprehensive survey of laser parameters
Aiko Narazaki, Hideyuki Takada, Dai Yoshitomi, Kenji Torizuka, Yohei Kobayashi
Abstract
The productivity and quality of laser micromachining depend on multiple laser parameters that are intricately correlated. For these optimizations, a quick survey of laser parameters is vital. Recently, the authors developed a Yb-doped fiber chirped-pulse amplification system that can control various laser parameters in a wide range (pulse duration: 0.4–400 ps, repetition: single shot to 1 MHz, etc.). In this work, using this laser system, percussion microdrilling of three types of advanced ceramics, AlN, Al2O3, and Y2O3-doped ZrO2, was explored. In the case of the microdrilling of the Al2O3 ceramic, the ablation volume increased about 2–3 times as the pulse repetition increased from 100 Hz to 1 MHz. This suggests a different mechanism because the volume removal became dominant at 1 MHz. Scanning electron microscope observation confirmed a drastic melt formation at 1 MHz. From these, there is an additional volume removal due to the heat accumulation by multipulse irradiation on the Al2O3 ceramic at a higher repetition rate. It was also found that the variation of ablation volume with the pulse duration and fluence exhibited a big difference among these ceramics. A comprehensive survey of ultrafast laser ablation of ceramics was demonstrated.