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Laser and Plasmas

The interaction of intense laser radiation with matter leads to the formation of a plasma. The analysis of the radiation generated by the plasma gives access to the mechanisms involved into the processes of material ablation, plasma formation, and plume expansion. In particular, ablation by nanosecond laser pulses leads to a large rate of atomization and a high brilliance of the laser-produced plasma. These features are due to the interaction of laser beam with the vaporized material, leading to efficient plasma heating during the initial stage of expansion. Contrarily, when ultrashort laser pulses are applied, the energy is deposited in the electronic system and transferred to the matrix after the absorption of the laser energy. This situation leads to a strong gradient of temperature within the ablation plume with the most energetic particles in the leading edge. At strong laser irradiance, the plasma produced by ultrashort laser pulses generates radiation of short wavelengths according to the high initial electron temperature (ASUR project). At moderate irradiance, the ablation process leads to the efficient generation of nanoparticles. The combination of small size with large temperature and electron density makes the laser plasma an ideal emission source for studies of the atomic or molecular structure. In particular, it enables investigations of the collisional broadening of spectral lines with a minimized influence of self-absorption. The understanding of the physics of the plasmas produced by laser-matter interaction is explored in developing new laser-based processes. Here, we focus our interest on material analysis via laser-induced breakdown spectroscopy (LIBS), and on the generation and detection of small particles.

Topics under investigation :

Characterization of laser-produced plasmas

Laser plasma for investigations of atomic or molecular structure

Generation and detection of small particles

Material analysis via laser-induced breakdown spectroscopy