How to realize an ultrafast electron diffraction experiment with a terahertz pump: A theoretical study

Abstract

To integrate a terahertz pump into an ultrafast electron diffraction (UED) experiment has attracted much attention due to its potential to initiate and detect the structural dynamics both directly. However, the deflection of the electron probe by the electromagnetic field of the terahertz pump alters the incident angle of the electron probe on the sample, impeding it from recording structural information afterwards. In this article, we studied this issue by a theoretical simulation of the terahertz-induced deflection effect on the electron probe, and came up with several possible schemes to reduce such effect. As a result, a terahertz-pump-electron-probe UED experiment with a temporal resolution comparable to the terahertz period is realized. We also found that MeV UED was more suitable for such terahertz pump experiment.

Intense low-noise terahertz generation by relativistic laser irradiating near-critical-density plasma

“…[1,2] THz pulses with a field over 1 MV/cm are important for nonlinear lattice excitations, [3] insulator-to-metal transitions, [4] photo-induced superconductivity, [5] and ultrafast control of ferroelectric polarization. [6] More intense milli-Joule (mJ) THz wave with field strength over GV/m can be applied to nonlinear pump-probe experiments [7][8][9] or provide opportunities for high-gradient acceleration of electrons. [10][11][12][13][14] Conventionally, gigantic accelerator facilities [15,16] and nonlinear crystals [17][18][19] are mainly used to produce intense THz radiation.…”