  The current state of the art in structural biology is led by NMR, X-ray
crystallography and TEM investigations. These powerful tools however all rely
on averaging over a large ensemble of molecules. Here, we present an
alternative concept aiming at structural analysis at the single molecule level.
We show that by combining electron holography and coherent diffraction imaging
estimations concerning the phase of the scattered wave become needless as the
phase information is extracted from the data directly and unambiguously.
Performed with low-energy electrons the resolution of this lens-less microscope
is just limited by the De Broglie wavelength of the electron wave and the
numerical aperture, given by detector geometry. In imaging freestanding
graphene, a resolution of 2 Angstrom has been achieved revealing the 660.000
unit cells of the graphene sheet from one data set at once. Applied to
individual biomolecules the method allows for non-destructive imaging and
imports the potential to distinguish between different conformations of
proteins with atomic resolution.
