Hydrodynamic expansion of a femtosecond laser produced plasma

Fluorescence measurements were used to investigate the hydrodynamic expansion of femtosecond laser produced microplasmas. The laser radiation was focused onto a copper sample under defined argon atmospheres. The expansion of the microplasma was investigated by fluorescence spectroscopy for different pressures and laser energies. Fluorescence for different heights and various delays were recorded by an échelle-spectrometer equipped with a gatable intensified charge coupled device. From the measurement, the expansion dynamics can be deduced and compared with the modified point blast model. The experiments were found to be in good agreement with calculations based on this model.