Chinese Optics Letters, 2018, 16 (4): 041401, Published Online: Jul. 12, 2018
Numerical model and experimental demonstration of high precision ablation of pulse CO2 laser
140.3390 Laser materials processing 140.3470 Lasers, carbon dioxide 220.5450 Polishing 140.3538 Lasers, pulsed
Abstract
To reveal the physical mechanism of laser ablation and establish the prediction model for figuring the surface of fused silica, a multi-physical transient numerical model coupled with heat transfer and fluid flow was developed under pulsed CO 2 laser irradiation. The model employed various heat transfer and hydrodynamic boundary and thermomechanical properties for assisting the understanding of the contributions of Marangoni convention, gravitational force, vaporization recoil pressure, and capillary force in the process of laser ablation and better prediction of laser processing. Simulation results indicated that the vaporization recoil pressure dominated the formation of the final ablation profile. The ablation depth increased exponentially with pulse duration and linearly with laser energy after homogenous evaporation. The model was validated by experimental data of pulse CO 2 laser ablation of fused silica. To further investigate laser beam figuring, local ablation by varying the overlap rate and laser energy was conducted, achieving down to 4 nm homogenous ablation depth.
Ting He, Chaoyang Wei, Zhigang Jiang, Zhen Yu, Zhen Cao, Jianda Shao. Numerical model and experimental demonstration of high precision ablation of pulse CO2 laser[J]. Chinese Optics Letters, 2018, 16(4): 041401.