We report the development of 4D scanning
transmission ultrafast electron microscopy (ST-UEM). The
method was demonstrated in the imaging of silver nanowires
and gold nanoparticles. For the wire, the mechanical
motion and shape morphological dynamics were imaged,
and from the images we obtained the resonance frequency
and the dephasing time of the motion. Moreover, we
demonstrate here the simultaneous acquisition of dark-field
images and electron energy loss spectra from a single gold
nanoparticle, which is not possible with conventional methods.
The local probing capabilities of ST-UEM open new
avenues for probing dynamic processes, from single isolated
to embedded nanostructures, without being affected by the
heterogeneous processes of ensemble-averaged dynamics.
Such methodology promises to have wide-ranging applications
in materials science and in single-particle biological
imaging
