Max-Born-Institut, Berlin, Germany

报告摘要 
Above-threshold ionization (ATI) may be the "purest" phenomenon of intense-laser atom physics, since the experiment observes the single atom. Gross features are easily described by the so-called "simple-man model", which incorporates nothing but tunneling and classical mechanics of an electron in a laser field. For a detailed quantitative description, solution of the time-dependent Schrodinger equation is indispensable. The strong-field approximation (SFA) steers an intermediate course: it neglects the interaction of the electron with the laser field, as long as the former is bound, and the interaction with the binding potential, as soon as it is free. This simplification allows for expressions that can almost be evaluated analytically, and even more importantly, lend themselves to a physical interpretation. I introduce the SFA and discuss with its help various ATI effects, especially intensity-dependent enhancements of groups of ATI peaks. I also discuss efforts to introduce additional  atom-specific features into the SFA.

报告人简介 
Prof. Wilhelm Becker’s interest focuses on Atoms in intense fields, multiphoton processes, quantum optics, free-electron lasers and quantum electrodynamics in intense laser fields, etc. About 200 publications have been authored or co-authored in refereed journals and edited volumes. He was member of Editorial Board of Physical Review A during 1999 to 2004, Editorial Board of Laser Physics Letters in 2003, Fellow of American Physical Society and Optical Society of America in 2005, etc. Now he is member of the selection committee for the Max Born Award of the Optical Society of America.

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