Transmission electron microscopy (TEM) is a key method for understanding materials at the nanoscale, as it provides access to structural or atomic origins of macroscopic observations. Electron holography (EH) further deepens this microscopic insight by directly measuring the associated electric and magnetic fields at the same spatial resolution (see, e.g., [1]). To date, EH has been limited to static samples. Extending it to dynamic processes is challenging because the temporal resolution of EH is limited by the long exposure times (typically on the order of seconds) required to obtain data that are well above noise.

For reversible processes, this hurdle is usually overcome by pump-probe techniques. Pump-probe measurements of periodic processes require time gating for the time-dependent signal. In TEM, the required shutter/gating is realized either by using fast direct detection cameras with readout times per frame in the submillisecond range or by gating the beam from the detector by transverse electric or magnetic fields. For accelerating voltages in the range of 200 to 300 kV, the transients that occur when switching the required high currents or voltages prohibit time resolutions below the millisecond range.