报告时间：2016年12月26日（周一）下午15:30

报告地点：高等研究院会议室

报告人：刘海华

职务：Research Scientistin the group of Professor Ahmed Zewail (Nobel laureate in 　 Chemistry) at California Institute of Technology. c.

题目：4D Ultrafast Electron Microscopy

报告简介：

　　The 4D UEM technology pioneered by Professor Ahmed Zewail at Caltech since 2004 enables scientist to explore ultrafast events and process that occur at the atomic and molecular spatial scale over time spans measured in femtoseconds (10^-15 seconds), the time scale of atomic motions, which is 10 orders of magnitude better than that of conventional microscopes limited by the video-camera rate of recording. Now, 4D UEM has been extensively used in the study of ultrafast dynamicsfrom atomic motions during structural dynamics to phase transitions,nanomechanical oscillations, surface morphology dynamics, observing liquid flow in nanotube, charge density wave, chemical bonding, biology protein dynamics, crystallization etcby various developed UEM techniques. In this talk, I will introduce the development and progress that I made in 4D UEM, such as ultrafast phase transition study of single particle dynamics in VO₂ensemble,development of diffraction PINEM to improve energy resolution and study structural dynamics, Photo-gating to improve temporal resolution in UEM, 4D multiple cathode UEM, etc.