The beam coherence simulation of 1-dimensional nano-scale photocathode under high power laser irradiation

1-dimensional (1D) nano-scale photocathode with back-illumination is a promising technology for producing highly coherent electrons which may allow us to realize 4-dimensional space-time analysis of atomic structures. By simulation, we evaluated the coherence of electrons generated from gold cathode by taking into account laser-induced heating effect. The laser irradiation conditions for different cathode thickness were derived from 1D-Two Temperature Model (TTM). We also investigated the coherence of the beam by beam tracking simulation including conventional extracting electric field. Our result indicates that the beam coherence at the acceleration electron where the sample to measure is located is not sensitive to the initial beam coherence on the cathode surface.