title: Investigation of ultrashort pulse laser ablation of solid targets by measuring the ablation-generated momentum using a torsion pendulum.
abstract: 50 fs - 12 ps laser pulses are employed to ablate aluminum, copper, iron, and graphite targets. The ablation-generated momentum is measured with a torsion pendulum. Corresponding time-resolved shadowgraphic measurements show that the ablation process at the optimal laser fluence achieving the maximal momentum is primarily dominated by the photomechanical mechanism. When laser pulses with specific laser fluence are used and the pulse duration is tuned from 50 fs to 12 ps, the generated momentum firstly increases and then remains almost constant, which could be attributed to the change of the ablation mechanism involved from atomization to phase explosion. The investigation of the ablation-generated momentum also reveals a nonlinear momentum-energy conversion scaling law, namely, as the pulse energy increases, the momentum obtained by the target increases nonlinearly. This may be caused by the effective reduction of the dissipated energy into the surrounding of the ablation zone as the pulse energy increases, which indicates that for femtosecond laser the dissipated energy into the surrounding target is still significant.
authors.affiliation: Institute of Modern Optics, Nankai University, Key Laboratory of Opto-electronic Information Science and Technology, Ministry of Education, Tianjin, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.forename: Wentao
authors.initials: W
authors.lastname: Wang
authors.forename: Xiaonong
authors.initials: X
authors.lastname: Zhu
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Liu
authors.forename: Kuanhong
authors.initials: K
authors.lastname: Xu
authors.forename: Peng
authors.initials: P
authors.lastname: Huang
authors.forename: Jiefeng
authors.initials: J
authors.lastname: Zhao
authors.forename: Ruxin
authors.initials: R
authors.lastname: Li
authors.forename: Mingwei
authors.initials: M
authors.lastname: Wang
mesh_terms: D007834:Lasers; D008420:Manufactured Materials / Q000528:radiation effects*; D013499:Surface Properties / Q000528:radiation effects; D019415:Torque; D014159:Transducers