Numerical modeling of frequency conversion of high-intensity laser pulses into XUV/X and THz radiation

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In recent years there has been an intense research effort to develop powerful and coherent radiation sources in previously unused frequency ranges of great interest both for scientific research and practical applications. Two of these frequency ranges are the XUV/X and THz frequencies. Due to its high frequency, XUV/X radiation finds its important applications in atomic and molecular spectroscopy, characterization of plasmas, and in attoscience, and promises new applications in the context of microscopy applied to life and materials sciences. At the low-frequency end of the visible spectrum, the THz radiation promises important applications in the areas of remote chemical and structural integrity analysis, and in security. A common point between XUV/X and THz radiation is that both can be generated from the interaction of a high-intensity femtosecond laser pulse and a low density medium - gas or plasma. The main current challenge in both XUV/X and THz generation is to increase the yield of the sources and, in the case of XUV/X, extend the spectrum as far as possible towards high frequencies (X-ray range), in order to obtain sufficient intensities to achieve the envisaged applications. The general goal of this research program is to investigate theoretically the frequency conversion process of high intensity laser pulses in low density media, with emphasis on the generation of XUV/X and THz radiation. The modeling tools that will be developed within this research program will allow to: (i) improve our general understanding of the physical processes, (ii) optimize the experimental setups, and (iii) investigate through numerical simulations new more sophisticated experimental arrangements to increase the yield in the frequency ranges of interest. These computer tools will be key components of a "modeling toolbox" that can be applied in the future to many other problems related to the interaction between high-intensity laser pulses and low-density media.