报告主题：Time-resolved photoemission and collective excitations by attosecond streaking technique
报告人：KárolyTőkési 教授
时间：2016年7月18日(周一) 下午 14:00
地点：教十一大楼318会议室
邀请人：田鹤 研究员
摘要:
Attosecond physics is a new and rapidly developing field driven by recent advances in laser technology. Attosecond science holds the promise to observe and to control the motion of electrons on their natural time scale. It is now possible to take snapshots of electrons in motion in atoms, molecules, and solids. The long-lasting dream of chemists and physicists to watch and to control in real time the formation and breaking of chemical bonds or electrons leaving an atom is now closer to realization than ever. These experimental advances pose considerable challenges for theory.
Time-resolved photoemission experiments employing attosecond streaking of electrons emitted by an extended ultraviolet pump pulse and probed by a few-cycle near-infrared pulse found a time delay of about 100 as between photoelectrons from the conduction band and those from the 4f core level of tungsten. We present a microscopic simulation of the emission time and energy spectra employing a classical transport theory. Our calculations reproduced well both the emission spectra and streaking images. We found delay times near the lower bound of the experimental data.
Photoemission spectra feature also complex correlation satellite structures signifying the simultaneous excitation of single or multiple plasmons. The time delay of the plasmon satellites relative to the main line can be resolved in attosecond streaking experiments. Time-resolved photoemission thus provides the key to discriminate between intrinsic and extrinsic plasmon excitation. We demonstrate the determination of the branching ratio between intrinsic and extrinsic plasmon generation for simple metals.
报告人介绍：
Károly TőkésiScientific adviser, Institute for Nuclear Research, Hungarian Academy of Sciences(ATOMKI), Debrecen, Hungary
Education:
D.Sc. Hungarian Academy of Sciences, Budapest, Hungary, 2010
Habilitation, Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI),Debrecen, Hungary, 1999
Ph.D. equivalent in Physics, Kossuth Lajos University, Debrecen, Hungary, 1998
Dr.Univ. in Physics, Kossuth Lajos University, Debrecen, Hungary, 1991
M.Sc. in Physics, Kossuth Lajos University, Debrecen, Hungary, 1986
Research Experience:
Electronoptics
Electron spectroscopy
Electron-atom, ion-atom collision studies
Classical Trajectory Monte Carlo calculations
Electron energy loss spectroscopy
XPS and Auger spectroscopy
Simulation of electron spectra using Monte Carlo techniques
Awards:
1992 – Award for young Scentists from the Hungarian Acedemy of Science
1997 - Award for young Scentists from the Hungarian Acedemy of Science
2005 - the grant "Bolyai" from the Hungarian Academy Sciences -prominent qualification
2006 - Bolyai- plaquette - Hungarian Acedemy of Science
2008 –SzalaySándor award - Roland Eötvös Physical Society
2010 - the grant "Bolyai" from the Hungarian Academy Sciences -prominent qualification
Publications:
534 in referred journals or volumes
3 book chapter
1816 fully independent citations
Com. Impact factor: 371,230
Expected IF: 8,583
H-index: 28
