This equation shows microscopy resolution as a function of the light wavelength employed.
The electron microscopy (SEM) technique is similar to visible light, but the former uses an electron beam instead of a visible light beam. Electron microscope resolution is higher than optical microscope because the smaller wavelength of the electrons.
The figure in the slide shows a clear differentiation between both techniques in according to SEM and LOM instrumental features.
Different experimental methods may be employed in electron microscopy analysis, such as contrast, simple and direct replica, etc., as in optical microscopy.