Electron-optical metrology with femtosecond time resolution (theory and experiment)

The principles of simultaneous spatial and temporal focusing of photoelectron beams in nonstationary electric fields are theoretically studied and experimentally realised as applied to time-analysing image-converter tubes (ICTs). It is theoretically shown that the use of nonstationary focusing electric fields makes it possible to surpass the theoretical time resolution limit of ICTs (10^–4 s) determined for stationary fields by Zavoisky and Fanchenko in the 40s—50s of the last century. The possibility of forming electron packets with an energy of 10—30 KeV and a subfemtosecond duration (below 10^–15 s) gives impetus to the development of time-resolved electron diffraction, which is a direct method of investigation of atomic-molecular dynamics in solid and gaseous media.