Functions of the STEAM device. (a) Acceleration of electron beam with electron energy spectra for input beam (blue curve) and accelerated beam (red curve). (b) Temporal compression of the electron pulses as a function of the THz field in the rebunching mode. (c) Transverse electron beam focusing as a function of the THz field in the focusing mode. (d) Images of the electron beam on the detector with and without the THz deflection field in the streaking mode [6].