Optical properties of laser-produced plasmas

The interaction of high intensity femtosecond laser pulses with matter allows the production of plasmas with high electron densities. This enables the study of basic plasma physics in regimes relevant to astrophysics, atomic physics, or in strongly correlated plasmas. Much of the understanding of such plasmas depends on the knowledge of the optical properties. The diagnostic requires theoretical models for the interpretation of experimental data. We study the dielectric function and the electric conductivity in the framework of a generalized DRUDE model. The required collision frequencies are taken in BORN and strong coupling (T-matrix) approximations. Furthermore, we try to give an estimation of the influence of nonlinear, high frequency effects of the electrical field. In order to describe the temporal evolution of the plasma, we determine the composition of the plasma solving Saha's equation. Therefore we investigate different approximations for the effective ionization energy including Pade formulas for the correlation part of the chemical potential.