Third-generation femtosecond technology (3FST) offers the potential for femtosecond light tunable over several octaves, multi-terawatt few-cycle pulses, and synthesized multi-octave light transients. Unique tunability, temporal confinement, and waveform variety in combination with unprecedented average powers will extend nonlinear optics and laser spectroscopy to previously inaccessible wavelength domains, ranging from the far IR to the x-ray regime. The underlying concepts, technologies, and proof-of-principle experiments are being currently explored in several laboratories around the world. A conceptual design study of a prototypical tunable and wideband source demonstrates the potential of 3FST for pushing the frontiers of femtosecond and attosecond science. The consequences, from a theoretical viewpoint, of the utilization of these laser sources to drive strong field phenomena are still unexplored. Only few attempts have been done so far, but still many questions remain to be answered.

The aim of this project is to theoretically study strong field phenomena, for example high-order harmonic generation (HHG), above-threshold ionization (ATI) and multiple ionization, driven by multi-octave light transients and to explore the ultimate limits, under the guidance of experimental colleagues.