D'Abzac F. X., Seydoux-Guillaume A. M., Chmeleff J., Datas L., Poitrasson Franck. (2012). In situ characterization of infrared femtosecond laser ablation in geological samples. Part A : the laser induced damage. Journal of Analytical Atomic Spectrometry, 27 (1), p. 99-107. ISSN 0267-9477.
Titre du document
In situ characterization of infrared femtosecond laser ablation in geological samples. Part A : the laser induced damage
D'Abzac F. X., Seydoux-Guillaume A. M., Chmeleff J., Datas L., Poitrasson Franck
Source
Journal of Analytical Atomic Spectrometry, 2012,
27 (1), p. 99-107 ISSN 0267-9477
Infrared femtosecond laser induced damage has been studied in order to determine, with analytical protocols, the processes involved in laser ablation in this regime. Transmission Electron Microscopy (TEM) coupled with Focused Ion Beam (FIB) milled cross-sections of natural ablated monazite were used. Craters were formed using N = 1 and 3 shots, E(0) = 0.1 and 0.8 mJ per pulse and tau = 60 fs. Observations revealed that laser settings induce little changes in the nature and size of damaged structures. The crater bottom forms a similar to 0.5 mm layer composed of melted and recrystallized monazite grains, and spherical similar to 10 nm voids. The underlying sample shows lattice distortions, progressively attenuated with depth, typical of mechanical shocks (thermoelastic relaxation and plasma recoil pressure). No chemical difference appears between these two domains, excluding preferential vaporization and thus laser induced chemical fractionation. Correlations with existing molecular dynamics (MD) simulations indicate that the deep distorted lattice probably undergoes spallation whereas the upper layer rather goes through homogeneous nucleation. Nevertheless, these processes are not pushed forward enough to induce matter removal in the present conditions. In consequence, photomechanical fragmentation and vaporization, requiring higher energy density states, would rather be the main ablation mechanisms. This hypothesis was supported by an additional study focused on the laser produced aerosols. Further links to LA-ICP-MS measurements can then be developed.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Géologie et formations superficielles [064]
