New optical device opens path for extreme focusing of X-rays

Adaptable refractive correctors for X-ray optics

An innovative new type of optical component for X-rays has been developed by a scientific team in the Optics and Metrology Group at Diamond Light Source. This new optical component is designed to correct for the effect of imperfections in the optical elements used for focusing of X-rays. It works by introducing a controlled change to the X-ray’s phase. It is known as an “adaptable refractive corrector” – so called because the corrector uses refraction and can  adapt  the correction to the unique imperfection of any optical element. The researchers have designed and tested such a component at Diamond obtaining reductions in the effect of the imperfections in a range of mirror and lens focusing optical elements by a factor of up to 7. This development is expected to have application to new developing techniques such as hard X-ray microscopy at the nanometre scale.

>Read more on the Diamond Light Source website

Image: Schematic showing the adaptable corrector with a double mirror system.

Virtual lens improves X-ray microscopy

PSI researchers are first to transfer state-of-the-art microscopy method to X-ray imaging

X-rays provide unique insights into the interior of materials, tissues, and cells. Researchers at the Paul Scherrer Institute PSI have developed a new method that makes X-ray images even better: The resolution is higher and allows more precise inferences about the properties of materials. To accomplish this, the researchers moved the lens of an X-ray microscope and recorded a number of individual images to generate, with the help of computer algorithms, the actual picture. In doing so they have, for the first time ever, transferred the principle of so-called Fourier ptychography to X-ray measurements. The results of their work, carried out at the Swiss Light Source SLS, are published in the journal Science Advances.

>Read more on the Swiss Light Source at PSI website

Image: Klaus Wakonig and Ana Diaz, together with other PSI researchers, have transferred the principle of Fourier ptychography to X-ray microscopy for the first time ever.
Credit: Paul Scherrer Institute/Markus Fischer

Shining a new light on biological cells

Combined X-ray and fluorescence microscope reveals unseen molecular details

A research team from the University of Göttingen has commissioned at the X-ray source PETRA III at DESY a worldwide unique microscope combination to gain novel insights into biological cells. The team led by Tim Salditt and Sarah Köster describes the combined X-ray and optical fluorescence microscope in the journal Nature Communications. To test the performance of the device installed at DESY’s measuring station P10, the scientists investigated heart muscle cells with their new method.

Modern light microscopy provides with ever sharper images important new insights into the interior processes of biological cells, but highest resolution is obtained only for the fraction of biomolecules which emit fluorescence light. For this purpose, small fluorescent markers have to be first attached to the molecules of interest, for example proteins or DNA. The controlled switching of the fluorescent dye in the so-called STED (stimulated emission depletion) microscope then enables highest resolution down to a few billionth of a meter, according to principle of optical switching between on- and off-state introduced by Nobel prize winner Stefan Hell from Göttingen.

>Read more on the PETRA III at DESY website

Image: STED image (left) and X-ray imaging (right) of the same cardiac tissue cell from a rat. For STED, the network of actin filaments in the cell, which is important for the cell’s mechanical properties, have been labeled with a fluorescent dye. Contrast in the X-ray image, on the other hand, is directly related to the total electron density, with contributions of labeled and unlabeled molecules. By having both contrasts at hand, the structure of the cell can be imaged in a more complete manner, with the two imaging modalities “informing each other”.
Credit: University of Göttingen, M. Bernhardt et al.

Perovskites, the rising star for energy harvesting

Perovskites are promising candidates for photovoltaic cells, having reached an energy harvesting of more than 20% while it took silicon three decades to reach an equivalent. Scientists from all over the world are exploring these materials at the ESRF.

Photovoltaic (PV) panels exist in our society since several years now. The photovoltaic market is currently dominated by wafer-based photovoltaics or first generation PVs, namely the traditional crystalline silicon cells, which take a 90% of the market share.

Although silicon (Si) is an abundant material and the price of Si-PV has dropped in the past years, their manufacturing require costly facilities. In addition, their fabrication typically takes place in countries that rely on carbon-intensive forms of electricity generation (high carbon footprint).

But there is room for hope. There is a third generation of PV: those based on thin-film cells. These absorb light more efficiently and they currently take 10% of the market share.

>Read more on the European Synchrotron website

Image: The CEA-CNRS team on ID01. From left to right: Peter Reiss, from CEA-Grenoble/INAC, Tobias Schulli from ID01, Tao Zhou from ID01, Asma Aicha Medjahed, Stephanie Pouget (both from CEA-Grenoble/INAC) and David Djurado, from the CNRS. 
Credits: C. Argoud.