In a joint research project, scientists from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI), the Technische Universität Berlin and the University of Rostock have managed for the first time to image free nanoparticles in a laboratory experiment using a high-in ... more
Laser takes pictures of electrons in crystals
The experiments pave the way towards to deeply understand and eventually control the chemical and the electronic properties of materials
Microscopes of visible light allow us to see tiny objects such living cells and their interior. Yet, they cannot discern how electrons are distributed among atoms in solids. Now researchers around Prof. Eleftherios Goulielmakis of the Extreme Photonics Labs at the University of Rostock and the Max Planck Institute of Quantum Optics in Garching, Germany, along with coworkers of the Institute of Physics of the Chinese Academy of Sciences in Beijing, developed a new type of a light microscope, the Picoscope, that allows overcoming this limitation.
The researchers used powerful laser flashes to irradiate thin, films of crystalline materials. These laser pulses drove crystal electrons into a fast wiggling motion. As the electrons bounced off with the surrounding electrons, they emitted radiation in the extreme ultraviolet part of the spectrum. By analyzing the properties of this radiation, the researchers composed pictures that illustrate how the electron cloud is distributed among atoms in the crystal lattice of solids with a resolution of a few tens of picometers which is a billionth of a millimeter. The experiments pave the way towards developing a new class of laser-based microscopes that could allow physicists, chemists, and material scientists to peer into the details of the microcosm with unprecedented resolution and to deeply understand and eventually control the chemical and the electronic properties of materials.
For decades scientists have used flashes of laser light to understand the inner workings of the microcosm. Such lasers flashes can now track ultrafast microscopic processes inside solids. Still they cannot spatially resolve electrons, that is, to see how electrons occupy the minute space among atoms in crystals, and how they form the chemical bonds that hold atoms together. The reason is long known. It was discovered by Abbe more than a century back. Visible light can only discern objects commensurable in size to its wavelength which is approximately few hundreds of nanometers. But to see electrons, the microscopes have to increase their magnification power by a few thousand times.
To overcome this limitation, Goulielmakis and coworkers took a different path. They developed a microscope that works with powerful laser pulses. They dubbed their device as the Light Picoscope. "A powerful laser pulse can force electrons inside crystalline materials to become the photographers of the space around them." When the laser pulse penetrates inside the crystal, it can grab an electron and drive it into a fast- wiggling motion. "As the electron moves, it feels the space around it, just like your car feels the uneven surface of a bumpy road," said Harshit Lakhotia, a researcher of the group. When the laser-driven electrons cross a bump made by other electrons or atoms, it decelerates and emits radiation at a frequency much higher than that of the lasers. "By recording and analyzing the properties of this radiation, we can deduce the shape of these minute bumps, and we can draw pictures that show where the electron density in the crystal is high or low," said Hee-Yong Kim, a doctorate researcher in Extreme Photonics Labs. "Laser Picoscopy combines the capability of peering into the bulk of materials, like x-rays, and that of probing valence electrons. The latter is possible by scanning tunneling microscopes but only on surfaces.”
"With a microscope capable of probing, the valence electron density we may soon be able to benchmark the performance of computational solid-state physics tools," said Sheng Meng, from the Institute of Physics, Beijing, and a theoretical solid-state physicist in the research team. "We can optimize modern, state-of-the-art models to predict the properties of materials with ever finer detail. This is an exciting aspect that laser picoscopy brings in," he continues.
Now the researchers are working on developing the technique further. They plan to probe electrons in three dimensions and further benchmark the method with a broad range of materials including 2-D and topological materials. "Because laser picoscopy can be readily combined with time-resolved laser techniques, it may soon become possible to record real movies of electrons in materials. This is a long-sought goal in ultrafast sciences and microscopies of matter" Goulielmakis concludes.
- light microscopes
- material science
For the first time, a German-American research team has determined the three-dimensional shape of free-flying silver nanoparticles, using DESY's X-ray laser FLASH. The tiny particles, hundreds of times smaller than the width of a human hair, were found to exhibit an unexpected variety of sh ... more
Research and industry are increasingly exploiting the potential of aptamers. As well as their application in research, medical diagnosis and treatment, aptamers are also interesting as a basis for biosensors for use in environmental analysis because their characteristics enable them to iden ... more
A new study carried out by a team of laser physicists, molecular biologists and physicians based at LMU Munich and the Max Planck Institute for Quantum Optics has confirmed the temporal stability of the molecular composition of blood in a population of healthy individuals. The data provide ... more
Scientists at the Max Planck Institute of Quantum Optics (MPQ) have succeeded in testing quantum electrodynamics with unprecedented accuracy to 13 decimal places. The new measurement is almost twice as accurate as all previous hydrogen measurements combined and moves science one step closer ... more
At the biochemical level, organisms can be thought of as complex collections of different species of molecules. In the course of their metabolism, biological cells synthesize chemical compounds, and modify them in multifarious ways. Many of these products are released into the intercellular ... more
Cancer cells are smart when it comes to anti-cancer drugs, evolving and becoming resistant to even the strongest chemotherapies over time. To combat this evasive behavior, researchers have developed a method named D2O-probed CANcer Susceptibility Test Ramanometry (D2O-CANST-R) to see, at si ... more
Researchers from the Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences recently developed a new platform for rapid chiral analysis, producing chromatogram-like output without the need for separation. The study was published in Cell Reports Physical Science. Molecule ... more
Tumor cells circulating in blood are markers for the early detection and prognosis of cancer. However, detection of these cells is challenging because of their scarcity. In the journal Angewandte Chemie, scientists have now introduced an ultrasensitive method for the direct detection of cir ... more
- 1Detect neurodegenerative diseases such as Alzheimer's by a simple eye scan?
- 2Fluorescence microscopy at highest spatial and temporal resolution
- 3The Mechanics of the Immune System
- 4Resolve Biosciences Launches New Era in Single-Cell Spatial Analysis
- 5Quick look under the skin
- 6New ion trap to create the world's most accurate mass spectrometer
- 7How does your computer smell?
- 8Clocking electron movements inside an atom
- 9Sartorius closes 2020 with strong growth
- 10A clear path to better insights into biomolecules