Table-top soft X-ray absorption spectroscopy based on high average/peak power femtosecond laser

点击翻译按钮获取中文摘要

The discovery of X-rays in 1895 by Dr. William Roentgen has been an important step towards major breakthroughs in the last century. In medicine, this has had a major impact on our society by providing physicians with unique tools for diagnostics and treatments. In scientific research, X-rays are used for spectroscopic and structural characterization of atoms, molecules, biological structures and materials. Today, researchers from a broad diversity of scientific horizons, including biologists, chemists and physicists, are anticipating using X-ray laser pulses to probe dynamical processes with combined high spatial and high temporal resolutions. This quest motivates the construction of X-ray Free Electron Laser (XFEL) facilities around the world providing femtosecond X-ray laser pulses of high brilliance. The drawback of such facility, on top of its huge financial investment of billions of Euros, is its limited availability thus restraining the number of experiments that can be performed.Using the process of high harmonic generation (HHG), we will develop a table-top high flux X-ray laser to perform absorption measurements up to the Oxygen k-edge (2.4 nm) in oxide materials. To reach a high flux of soft X-ray photons, a new laser technology will be developed based on the concept of Frequency domain Optical Parametric Amplification - FOPA. This disruptive technology, developed by the INRS researchers, enables the efficient amplification of ultrashort pulses in the mid-infrared spectral range. Using a high average power picosecond pump laser for the FOPA, up to 50 W of average power will be available within 20 femtosecond pulses at 2 microns at a repetition rate of 10 kHz. Such a laser system will pave new applications for material characterization with X-rays, but also for the development of compact accelerators and bright THz sources.