Perspectives of ultrafast hyperspectral imaging in Scanning Electron Microscopy

Scanning Electron Microscopy (SEM) is commonly associated with rapid and effective morphological imaging of bulk sample at nanoscale, which alone makes it a pervasive tool present in a large variety of experimental laboratories and all at once limits SEM’s role to a complementary characterization tool. The last years mark the introduction in SEM of high performant energy selective filtering in the SEM’s electron energy and time, with resolutions down to few meV and below ps. These advances have the potential to open bulky specimens and surface properties to analytical and dynamical imaging capabilities similar, and complementary, to what scanning and traditional TEM have already demonstrated for thin samples. SEM struggles however to demonstrate the hyperspectral imaging capabilities of electronic, structural and collective excitations imaging in nanostructured devices and bulky specimens that may be expected from these technical figures of merit. In this talk, I will comment on the perspectives of the novel hyperspectral and dynamical imaging capabilities appearing in the SEM scenario, based on experimental results in recent years. I will then discuss possible approaches to merge in a multidimensional SEM microscopy some of the present frontier filtering capabilities: energy, time, and momentum. Several of these advanced filters can operate simultaneously in a tabletop SEM instrument, possibly in operando conditions. This approach has the potential of granting to small laboratories the nanoscale surface mapping of electronic band structure and collective phenomena into advanced materials and devices, which are presently tackled only at large scale facilities or by destructive approaches.