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Biomedical subjects

Hannes Lichte

Publications and source records attributed to Hannes Lichte.

3 recordsLinked to original sources

Electron interference: mystery and reality.

Interference of electron waves has developed from a fascinating phenomenon in basic physics to a key method for the highly sophisticated investigation of both electric and magnetic structures in solid-state materials. After more than 20 years of development, electron holography in the transmission electron microscope is now a very powerful technique for the analysis of micro-fields down to atomic dimensions. The applications extend from highly sensitive measurements in semiconductor technology to the quantitative characterization of atomic structures.

Electromagnetic Fields↗

Ferroelectric electron holography.

Ferroelectrics are increasingly important as materials in semiconductor technology, e.g. for building non-volatile memory chips. For optimisation of the properties of such devices, there is an urgent need for methods, which analyse the ferroelectric properties at nanometer scale. Furthermore, the basic understanding of the interaction of ferroelectrics with electrons in the transmission electron microscopy is still incomplete. It is shown that electron holography offers a promising way to understand and investigate ferroelectrics in the electron microscope.

Journal Article↗

Tutorial on off-axis electron holography.

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.

Holography↗