Laser ablation of a turbid medium modelling and experimental results

F. Brygo (1) , A. Semerok (1) , J.-M. Weulersse (1) , P.-Y. Thro (1) , R. Oltra (2)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 LRRS - Laboratoire de Recherche sur la Réactivité des Solides

Q -switched Nd:YAG laser ablation of a turbid medium (paint) is studied. The optical properties (absorption coefficient, scattering coefficient, and its anisotropy) of a paint are determined with a multiple scattering model (three-flux model), and from measurements of reflection-transmission of light through thin layers. The energy deposition profiles are calculated at wavelengths of 532 nm and 1.064 $\mu$m. They are different from those described by a Lambert-Beer law. In particular, the energy deposition of the laser beam is not maximum on the surface but at some depth inside the medium. The ablated rate was measured for the two wavelengths and compared with the energy deposition profile predicted by the model. This allows us to understand the evolution of the ablated depth with the wavelength: the more the scattering coefficient is higher, the more the ablated depth and the threshold fluence of ablation decrease

Mots clés: / modelisation; Interaction laser-matiere / Ablation de peinture

Domaines: Analyse numérique [cs.NA]; Physique Nucléaire Expérimentale [nucl-ex]

F. Brygo, A. Semerok, J.-M. Weulersse, P.-Y. Thro, R. Oltra. Laser ablation of a turbid medium modelling and experimental results. Journal of Applied Physics, 2006, 100 (3), pp.033106. ⟨10.1063/1.2220647⟩. ⟨cea-02360121⟩