Optimal imaging techniques in the scanning transmission electron microscope: applications to biological macromolecules.

We show applications of the optimal imaging method to stained biological macromolecules. This optimal imaging method involves the following basic procedures: (i) for any given resolution, which is represented by the electron probe size in the scanning transmission electron microscope, a preferred magnification is used; (ii) the micrographs taken at the condition described above are then spatially filtered by using a low-pass filter (nu < 1/2d, in which d is the space between scan lines) to optically reconstruct the final optimal image. It is found that the micrographs obtained by using the optimal imaging method clearly show an improvement in contrast.