Attosecond spectroscopy in solids

In this lab we employ a XUV-IR pump-probe scheme to perform experiments with attosecond temporal resolution on solid state targets. The ultimate goal of these experiments is to widen our knowledge of strong field driven processes and coherent optical response of solid materials toward their possible exploitation in PHz electronic devices.


The laser source is a Ti:Sapphire system with multistage amplification that provides 25 fs pulses with an energy of 2mJ at a repetition rate of 10 kHz with CEP stabilization. The duration of these pulses is compressed down to about 5 fs with a hollow core fiber compression system in combination with ultrabroadband chirped mirrors keeping an energy above 800 µJ.


The first part of the beamline is an actively stabilized interferometer, necessary for the generation of the two delayed replicas for the pump-probe experiments. XUV attosecond radiation is generated via High-order Harmonic Generation in noble gas. After collinear recombination, the two pulses are first focused on a gas target in correspondence of a TOF spectrometer where, during the experiments, a photoelectron streaking trace is acquired. This will be used to know the exact field acting on the sample during the experiment. The pulses are then refocused on the solid target under investigation. The reflected XUV radiation is recorded via an XUV spectrometer as a function of the delay from the IR pump pulse.