"Ultrafast coherent x-rays from tabletop lasers—a new tool for science and technology"
University of Colorado
The discovery of x-rays made possible not-only new medical technologies, but also allowed man to “see” for the first time at the atomic scale, revolutionizing our understanding of matter. Efforts to bring x-ray techniques to femtosecond time-scales—the fundamental atomic time scale— have been ongoing for the past ~¼ century, and are now providing new insight into the behavior of matter. Key to this work has been to understand the coherent high-order harmonic generation (HHG) upconversion process. HHG allows for the light from a high-power femtosecond laser to be coherently upconverted from the infrared into the soft x-ray region of the spectrum, with each x-ray photon resulting from the coherent combination of hundreds or even thousands of photons from the driving laser. The resultant ultrashort-pulse HHG x-ray sources allow us to probe, using a tabletop setup, the fastest charge, spin and energy transport processes. The capabilities of these sources have increased dramatically with our recent demonstration of bright sources with photon energy >1 keV.[1-4] Recent applications include probing the dynamics of the quantum exchange interaction fundamental to magnetic materials;[5-7] the use of coherent HHG light for tabletop nano-imaging with record resolution; and studies of the physical limits of energy flow at the nanoscale.[9,10]
Thursday, November 29, 2012
Hawking Auditorium, 4:00 p.m.
Mitchell Physics Institute
Department of Physics and Astronomy
Texas A&M University
(Refreshments to be served at 3:45pm in the Penrose Plaza)
Host: Alexey Belyanin