PHOTON SCIENCE

DESYs X-ray laser FLASH observes molecular explosion

Using DESY’s X-ray laser FLASH, a team of scientists from Hamburg has traced the ultrafast explosion of iodine molecules. The group headed by Markus Drescher from the Center for Free-Electron Laser Science (CFEL) used the X-ray laser as a kind of high-speed camera –the observed molecular explosion took place within a millionth of a billionth of a second (i.e. within femtoseconds). The scientists presented their measurements in the ...

Physicists demonstrate crucial method for monitoring ultra short X-ray pulses

With their ultra short X-ray flashes, free-electron lasers offer the opportunity to film chemical reactions or atoms in motion. However, for this super slow motion the arrival time and the temporal profile of the pulses must be precisely known. An international team of scientists has now developed a measurement technique that provides complete temporal characterization of individual FEL (free-electron laser) pulses at DESY´s soft-X-ray ...

Free-electron laser FLASH reveals fast optical demagnetisation process (Oct. 2012)

The prerequisite of this kind of demagnetisation is that the basic material is divided into domains, which is usually the case with ferromagnets. Therefore, an unmagnetised iron bar consists of many microscopically small areas. Within these areas, the magnetisation has the same direction, but there is a random magnetisation of these miniature areas towards each other. When the iron bar is magnetised, for example when a magnetic field is applied from ...

Snapshots of Firework in Nanoparticles at FLASH: Beyond Conventional Ultrafast Spectroscopy (Mar.2012)

Any sample in the focus of an intense X-ray laser flash will be converted into a highly excited, nonequilibrium plasma hotter than the sun. The scattering signal is affected by the changes in the electronic structure of the sample, leading to modifications of the scattered light even though the particle geometry remains the same on the time scale of the interaction with the laser pulse. Conversely, the information carried by the scattering signal can be ...