Researchers determine the structure and dynamics of proteins using NMR (Nuclear Magnetic Resonance) spectroscopy. Until now, however, much higher concentrations were necessary for in-vitro measurements of the biomolecules in solution than found in our body's cells. An NMR method enhanced by ... more
New light for shaping electron beams
Adaptive imaging technique for materials science and structural biology
A new technique that combines electron microscopy and laser technology enables programmable, arbitrary shaping of electron beams. It can potentially be used for optimizing electron optics and for adaptive electron microscopy, maximizing sensitivity while minimizing beam-induced damage. This fundamental and disruptive technology was now demonstrated by researchers at the University of Vienna, and the University of Siegen. The results are published in PRX.
When light passes through turbulent or dense material, e.g. the Earth’s atmosphere or a millimetre-thick tissue, standard imaging technologies experience significant limitations in the imaging quality. Scientists therefore place deformable mirrors in the optical path of the telescope or microscope, which cancel out the undesired effects. This so-called adaptive optics has led to many breakthroughs in astronomy and deep-tissue imaging.
However, this level of control has not yet been achieved in electron optics even though many applications in materials science and structural biology demand it. In electron optics, scientists use beams of electrons instead of light to image structures with atomic resolution. Usually, static electromagnetic fields are used to steer and focus the electron beams.
In a new study published in PRX, researchers from the University of Vienna (at the Faculty of Physics and the Max Perutz Labs) and the University of Siegen have now shown that it is possible to deflect electron beams almost arbitrarily using high-intensity, shaped light fields, which repel electrons. Kapitza and Dirac first predicted this effect in 1933, and the first experimental demonstrations (Bucksbaum et al., 1988, Freimund et al., 2001) became possible with the advent of high-intensity pulsed lasers.
The Vienna-based experiment now makes use of our ability to shape light. A laser pulse is shaped by a spatial light modulator and interacts with a counter-propagating, synchronized pulsed electron beam in a modified scanning electron microscope. This enables imprinting on demand transverse phase shifts to the electron wave, enabling unprecedented control over electron beams.
The potential of this innovative technology is demonstrated by creating convex and concave electron lenses and by generating complex electron intensity distributions. As pointed out by the lead author of the study, Marius Constantin Chirita Mihaila: "We are writing with the laser beam in the transverse phase of the electron wave. Our experiments pave the way for wavefront shaping in pulsed electron microscopes with thousands of programmable pixels. In the future, parts of your electron microscope may be made from light."
In contrast to other competing electron-shaping technologies, the scheme is programmable, and avoids losses, inelastic scattering, and instabilities due to the degradation of material diffraction elements. Thomas Juffmann, head of the group at the University of Vienna, adds, "Our shaping technique enables aberration correction and adaptive imaging in pulsed electron microscopes. It can be used to adjust your microscope to the specimens you study to maximize sensitivity."
- electron microscopy
- laser technology
- electron beams
- structural biology
- material science
A small group of researchers including Dennis Kurzbach from the Faculty of Chemistry of the University of Vienna just published in "Nature Protocols" an advanced NMR (Nuclear Magnetic Resonance) method to monitor fast and complicated biomolecular events such as protein folding. For example, ... more
The predictions of researchers that certain particles of matter with sufficiently high density would form a new state - crystalline and flowing at the same time - could be confirmed in the laboratory. More than 20 years ago, researchers predicted that with sufficiently high density certain ... more
- 1Miniaturized infrared detectors
- 2A new tool for estimating people’s total exposure to potentially harmful chemicals is developed by Mount Sinai researchers
- 3Can smartphones predict mortality risk?
- 4Fighting tumours with magnetic bacteria
- 5Advances in spectroscopy
- 6New collaboration between Shimadzu and the University Medical Center Göttingen
- 7New Molecular Microscopy Uncovers how Breast Cancer Spreads
- 8Imaging cells: New method enables clear, precise look inside
- 9Smarter sensor sniffs out target gases
- 10Pharmacoscopy: Next-Generation Microscopy
- Growth of Nanoholes Visible for the First Time Thanks to Helium Scattering
- New light for shaping electron beams
- Three Eyes See More than Two - monitoring a catalytic reaction with three different microscopies under exactly the same conditions in real time
- Sniffing out carcinogens in foodstuffs
- Miniaturized Lab-on-a-Chip for real-time Chemical Analysis of Liquids