Light pulses from a femtosecond laser can be coherently upconverted to generate light in the soft x‑ray region of the spectrum using the technique of high-order harmonic generation. Advances in laser technology, combined with a better understanding of the high harmonic process , have made it possible to implement an ultrashort-pulse source of ionizing radiation with flux sufficient for a variety of application experiments  and with unique capabilities. For example, recently, we have done the first direct time-resolved studies of molecular fragmentation resulting from ionization , and have probed the angle-dependent photoionization cross section of laser-aligned molecules. The high-order harmonic generation process itself also can be used to probe molecular structure . In this talk I will give an overview of experiments in this area done in our group, and will discuss the technology and future prospects for tabletop-scale ultrafast x-ray sources.
 H. Kapteyn, O. Cohen, I. Christov, and M. Murnane, "Harnessing attosecond science in the quest for coherent X-rays," Science 317(5839), 775-778 (2007).
 R.L. Sandberg, C.Y. Song, P.W. Wachulak, D.A. Raymondson, A. Paul, B. Amirbekian, E. Lee, A. E. Sakdinawat, C. La-O-Vorakiat, M.C. Marconi, C.S. Menoni, M.M. Murnane, J.J. Rocca, H. C. Kapteyn, and J.W. Miao, "High numerical aperture tabletop soft x-ray diffraction microscopy with 70‑nm resolution," Proceedings of the National Academy of Sciences of the USA 105(1), 24‑27 (2008).
 E. Gagnon, P. Ranitovic, A. Paul, C.L. Cocke, M.M. Murnane, H.C. Kapteyn, and A.S. Sandhu, "Soft x‑ray driven femtosecond molecular dynamics," Science 317(5843), 1374-1378 (2007).
 X. Zhou, R. Lock, W. Li, N. Wagner, M.M. Murnane, and H.C. Kapteyn, "Molecular Recollision Interferometry in High Harmonic Generation," Phys. Rev. Lett. 100, 073902 (2008).
ANL Physics Division Colloquium Schedule