Speaker
Description
Understanding the complex nonlinear physical processes involved in laser ablation remains a challenge. A fundamental understanding of laser ablation can greatly aid in determining optimal parameters for detection techniques such as laser-induced breakdown spectroscopy (LIBS), a high-sensitivity technique for measuring the elemental composition of a material using an energetic laser to produce a plasma at its surface. Here, a 9 ns, 532 nm Nd:YAG laser was used to perform LIBS measurements of aluminum, brass, and coffee samples using three different laser focal spots (21 µm, 47 µm, and 96 µm) and five pulse energies (16 mJ to 82 mJ). For all samples, it was found that the total integrated plasma emission and plasma temperature increased with laser intensity; however, the rate of increase varied with focal spot size. Notably, dividing the total plasma emission by the spot area aligned all data points linearly with laser intensity. To interpret these results, experimental data were fitted using the laser ablation model by R. Hergenroder [1]. The good agreement between simulation and experiment provides insight into the relationship between mass ablation and focused spot size, as well as the increase in plasma temperature due to inverse bremsstrahlung as laser energy increases.
[1] R. Hergenröder, “A model of non-congruent laser ablation as a source of fractionation effects in LA-ICP-MS,” J. Anal. At. Spectrom. 21(5), 505–516 (2006).
| Keyword-1 | Laser Ablation |
|---|---|
| Keyword-2 | LIBS |
| Keyword-3 | Laser produced plasma |