Time-resolved laser-induced electron diffraction imaging with XUV + IR scheme

We extend the laser-induced electron diffraction (LIED) imaging technique by adding an extreme ultraviolet (XUV) pulse to the driving infrared (IR) laser pulse to control and enhance the LIED signals. The XUV and IR intensities are chosen such that the ionization is dominated by the XUV while the control of the continuum electron is governed by the IR and the delay between the two pulses. By analyzing numerical solutions of the time-dependent Schrodinger equation, we show that accurate laser-free elastic electron-target ion scattering differential cross section can be retrieved within this “pump-probe” scheme for the XUV photon energies within a few eV above or below the ionization threshold. More importantly, with the precise control of the electron emission time provided by the XUV pulse, not only the temporal resolution of the measurement can be improved, but orders of magnitude enhancement in the LIED signals can be observed, as compared to the standard LIED technique. An additional advantage of this scheme is that a relatively weak IR pulse can be used, thereby overcoming the difficulties associated with the depletion of the target ground state. We further analyze the sub-cycle ionization dynamics to understand the delay-dependence of the LIED yields.



This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under Award Number DE-SC0023192.