the material, surface termination maps can be acquired. Detector A detector is placed at the end of electron optical column. Usually, a phosphor screen is used to convert the electron image to a photon image. The choice of phosphor type is governed by resolution considerations. A multichannel plate detector that is imaged by a CCD camera can substitute phosphor screen. Time-resolved PEEM Compared to many other electron microscopy techniques, time-resolved PEEM offers a very high temporal resolution of only a few femtoseconds with prospects of advancing it to the attosecond regime. The reason is that temporal electron pulse broadening does not deteriorate the temporal resolution because electrons are only used to achieve a high spatial resolution. The temporal resolution is reached by using very short light pulses in a pump-probe setup. A first pulse optically excites dynamics like surface plasmons on a sample surface and a second pulse probes the dynamics after a certain waiting time by photoemitting electrons. The photoemission rate is influenced by the local excitation level of the sample. Hence, spatial information about the dynamics on the sample can be gained. By repeating this experiment with a series of waiting times between pump and probe pulse, a movie of the dynamics on a sample can be recorded. Laser pulses in the visible spectral range are typically used in combination with a PEEM. They offer a temporal resolution of a few to 100 fs. In recent years, pulses with shorter wavelengths have been used to achieve a more direct access to the instantaneous electron excitation in the material. Here, a first pulse in the visible excites dynamics near the sample surface and a second pulse with a photon energy significantly above the work function of the material emits the electrons. By employing additional time-of-flight or high-pass energy recording in the PEEM, information about the instantaneous electronic distribution in a nanostructure can be extracted with high spatial and temporal resolution. Efforts to achieve attosecond temporal resolution and with that directly record optical fields around nanostructures with so far unreached spatio-temporal resolution, are still ongoing. Limitations The general limitation of PEEM, which is common with most surface science methods, is that the PEEM operates only under fairly restricted vacuum conditions. Whenever electrons are used to excite a specimen or carry information from its surface there has to be a vacuum with an appropriate mean free path for the electrons. With