Principles and spectroscopic applications of High order Harmonic Generation

Atomic and molecular gases exposed to ultrashort and moderately intense laser pulses emit coherent radiation that appears in time domain as a train of attosecond light bursts and in the spectral domain as harmonics of the driving laser field extending up to several hundreds of eV This process known as High order Harmonic Generation HHG is nowadays exploited in several leading edge applications of Atomic and Molecular Physics In this colloquium we will provide a background about the physical mechanisms governing HHG and we will then present some hints about the technology behind it Afterwards we will discuss about two spectroscopic applications of HHG: the study of the giant resonance in Xenon and the retrieval of the Highest Occupied Molecular Orbital in simple molecules Refreshments are served at 14:45