Single Shot Ablation Craters with Ultra-Short Laser Pulses: A Comparative Study
D. P. Weber1, *, V. Sudesh1, H. Kerrigan2, S. R. Fairchild2, M. C. Richardson2
1Physical Sciences Department, College of Arts and Sciences, Embry-Riddle Aeronautical University. Daytona Beach, FL, 32114, USA
2Laser Plasma Laboratory, College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA
*weberd1@my.erau.edu (832) 533-1318
Laser ablation is a technique to remove material by irradiation. This work qualitatively studies the basic mechanisms of laser ablation on GaAs, Al, Ti, Cu, and ZnSe samples by two regimes: a focused 1064 nm, 14.6 mJ pulse of 8 ns duration from an Nd:YAG laser (ns regime) and a focused 800 nm, 4.2 mJ pulse of 50 fs duration from a Ti:Sapphire laser (fs regime). The materials were ablated in these two regimes to qualitatively investigate the extent of the dominating mechanisms, as seen clearly in their craters. By firing only single shots, the formations that were created remain intact.
The following diagnostics were used to view the craters: a white light interferometric microscope to determine the crater topography, an optical microscope for a more general view, and a scanning electron microscope (SEM) to view the regions smaller than the resolution of the previous instruments. Significant thermo-mechanical stress in the nanosecond regime and a sub-surface boiling layer in the femtosecond regime have been identified. This investigation has concluded and is under final analysis and preparation for publication.