NCTS (South)


DATE2012-12-27

TIME14:10

PLACER203, 2F, NCTS, NCKU

FIELDOther

SPEAKER Prof. Chii-Dong Lin - Kansas State University, USA

TITLEUltrafast dynamic imaging of molecules with Laser-induced Electron Diffraction Method

ABSTRACTWhen molecules are placed in an intense few-cycle laser pulse, electrons that are tunnel ionized earlier in the pulse may be driven back by the laser field to recollide with the parent ions. If these electrons are backscattered they would emerge as high-energy photoelectrons. Based on the quantitative rescattering (QRS) theory, we showed that the momentum spectra of these photoelectrons can be used to retrieve the structure of molecules. Using 2.0 micron mid-infrared lasers, we showed that the bond length of oxygen molecules shrinks by 0.1 angstrom in 5 femtoseconds, demonstrating dynamic imaging of molecules with sub-angstrom spatial and few-femtosecond temporal resolutions for the first time.