Subparticle Ultrafast Spectrum Imaging in 4D Electron Microscopy

Plasmon Probe When light of certain wavelengths strikes a metal surface, it sets the metal's electrons in motion along trajectories termed “plasmon modes.” Yurtsever et al. (p. 59 ; see the Perspective by Batson ) constructed a type of electron microscope that can probe the electric fields associated with this process by measuring the energy of a separate pulse of electrons that is bounced off the surface immediately (less than trillionths of a second) after the light strikes. The spatial resolution was sufficient to map intensities in distinct regions of a single silver nanoparticle.