Abstract

The first lasing of the LINAC Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory in 2009 was a revolutionary event for science. That year, a new class of X-ray sources, the free electron laser (FEL) was born. These sources can produce x-rays in ultrashort pulses down to a few femtoseconds, with high coherence and with extreme peak brightness, up to 10 orders of magnitude higher than existing synchrotrons. These machine have opened-up for radically new types of experiments in physics, chemistry and biology, and are expected to continue doing so in the coming years. New facilities and instruments are being built around the world, with now seven FELs built and in operation.

In this talk, I will first go through some key concepts of FEL operation, and then I will present some highlights from the first years of FEL science: mostly in the field of condensed matter physics, but with a broad overview of other research fields as well. Finally, I will go through the important ideas and strategies to keep in mind in order to write compelling beamtime proposals at these facilities. The goal will be to give simple guidelines that will hopefully help to broaden the ultrafast x-ray science community.

Biography

Stefano Bonetti obtained a Ph.D. in Materials Physics from KTH - Royal Institute of Technology, Stockholm, Sweden with a dissertation on spin torque driven magnetization dynamics (2011). He was a postdoctoral fellow in the research group led by Jo Stöhr and Hermann Dürr at Stanford University and at SLAC National Accelerator Laboratory, investigating ultrafast magnetic dynamics and imaging, using synchrotron and free-electron-laser x-ray radiation (2012 – 2014).

In August 2014 he joined the Department of Physics at Stockholm University as a Researcher. Since then, he has been awarded one of the International Career Grants (Swedish Research Council, Marie Curie Action), for the project "THz spin control", and a European Research Council Starting Grant for the project "Understanding the speed limits of magnetism”. Since January 2017, Stefano has a tenured position (Associate Professor equivalent) at Stockholm University, where he leads the group of Ultrafast Dynamics in Condensed Matter. In December 2017, Stefano was selected as Wallenberg Academy Fellow by the Royal Academy of Science, with the project “Ultrafast Coherent Control of Quantum Materials”. In 2018, he was awarded a grant from the Swedish Research Council for the project "Nonlinear phononics”.

His group’s research efforts focus on the use of strong laser fields (in particular in the near-infrared and terahertz range) to manipulate quantum materials on ultrafast time scales. The response of these materials is probed with femtosecond lasers or femtosecond x-ray pulses generated at free electron lasers. Particular focus is dedicated to the investigation of spin and phonon dynamics in condensed matter.