Through recent years, off-axis electron holography has helped
us to understand and to overcome some experimental restrictions
in transmission electron microscopy. With development of powerful
electron microscopes, slow-scan CCD cameras, and computers,
holography is not an academic technique anymore used by specialized
laboratories. Holography has proven its wide range of applications
in solving real-world problems in materials science and biology.
At medium resolution, that is, on nanometer scale, holography
allows access to large area phase contrast produced by magnetic
fields and electric potentials. In the high-resolution domain,
holography unveils its power by unscrambling amplitude and phase
of the electron wave, resulting in an improved lateral resolution
up to the information limit. Holography is a thoroughly
quantitative method, and, in combination with the perfect zero-loss
filtering inherent to this method, the interpretation of the
reconstructed data is strongly simplified. After outlining the
basics of holography, in this tutorial we focus on development
of a step-by-step procedure for recording and reconstruction
of holograms. At the end, some recent applications are discussed.
