title: Investigations of femtosecond-nanosecond dual-beam laser ablation of dielectrics.
abstract: We have conducted experimental investigations for the micromachining of dielectrics (fused silica) using an integrated femtosecond (fs) and nanosecond (ns) dual-beam laser system at different time delays between the fs and ns pulses. We found that the maximum ablation enhancement occurs when the fs pulse is shot near the peak of the ns pulse envelope. Enhancements up to 13.4 times in ablation depth and 50.7 times in the amount of material removal were obtained, as compared to fs laser ablation alone. The fs pulse increases the free electron density and changes the optical properties of fused silica to have metallic characteristics, which increases the absorption of the ns laser energy. This study provides an opportunity for efficient micromachining of dielectrics.
authors.affiliation: Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Cheng-Hsiang
authors.initials: CH
authors.lastname: Lin
authors.forename: Zheng-Hua
authors.initials: ZH
authors.lastname: Rao
authors.forename: Lan
authors.initials: L
authors.lastname: Jiang
authors.forename: Wu-Jung
authors.initials: WJ
authors.lastname: Tsai
authors.forename: Ping-Han
authors.initials: PH
authors.lastname: Wu
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Chien
authors.forename: Shean-Jen
authors.initials: SJ
authors.lastname: Chen
authors.forename: Hai-Lung
authors.initials: HL
authors.lastname: Tsai