Röntgen 2D Materials for "Pocket X-ray Lasers"
Swiss Knowhow boosting EU priority plans
The use of X-rays and that of lasers has fundamentally changed our society. Their combination has been realized in the last decade at a few sites around the world, where a fourth-generation beamline is in operation. "Pocket X-ray lasers" are an ambitious challenge.
X-rays have enabled a large number of uses in medicine, chemistry, physics, security, and so on. Unfortunately, X-ray emission relies on lamps of weak brilliance and whose beams are difficult to focus. The realization of a compact X-ray laser is a current challenge with immense scientific and technological advantages.X-ray lasers as fourth-generation beamlines are very powerful experimental platforms, but accessible on a discontinuous application basis. The development of small systems is the central goal of this project.
A promising technology towards turnkey tabletop systems is represented by plasmas. Microplasmas, either generated by means of laser irradiation of targets (LPP) or by means of gas discharg-es (DPP), can be routinely produced on a home lab tabletop. The radiation, for extreme conditions of plasma temperature and density, is in the soft x-ray domain. The most prominent advantage from plasma radiation is the emission of a monochromatic characteristic spectrum of lines. These lines are related to the stimulated relaxation of the collisionally excited states. Unfortunately plasmas have not been able to deliver hard X-ray lasers.
The fundamental idea investigated in this project is that x-ray fluorescence, resonant with the lattice parameter of the host material, may experience distributed feedback and gain. In the x-ray region, the natural periodicity of the electronic charge density in crystals hints at strong Bragg coupling, as proposed theoretically by Yariv 1974.