Development of a soft-x-ray attosecond transient absorption spectroscopy system with a mid-infrared laser driver

We will present the capabilities of a new soft-x-ray transient absorption spectroscopy system developed in our lab. The soft-x-ray generation occurs through high harmonic generation process, pumped by various MIR laser pulses. First, we used 1 micron wavelength driver followed by a hollow core fiber and chirped mirrors to produce broadband IR pulse that generates attosecond x-ray pulses in the range from 10-100 eV. Our second approach relies on the application of an OPCPA with tunable laser pulses from 1.5 to 3.4 micron, which provides access to 100-600 eV x-rays. An angular streaking detector characterizes the x-ray pulse duration. The transient absorption spectrometer forms the main diagnostic technique to be used for experiments geared to monitor the charge migration in molecules. We will present the first results obtained from using this system.