Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.
In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of a millimetre-sized chip capable of splitting a beam of X-rays [Acta Cryst. (2016), A72, doi:10.1107/S205327331601144X].
Fork-shaped channels that are only a few tens of nanometres wide and deep are transferred into a silicon wafer using electron-beam lithography and reactive ion etching then enclosed by bonding a second silicon wafer on top.
The results of simulations of how the 'parent' beam is split into two 'daughter' beams on passing through the chip were backed up by experimental measurements at the European Synchrotron Radiation Facility, showing that the incident beam is efficiently transported through the chip, neatly split and guided to exits that have precisely controlled (and tunable) spacings.
After the daughter beams leave the chip, they interfere, leading to a pattern of vertical stripes just like the pattern obtained from a classical Young's double-slit interference experiment. Interestingly, on close inspection there are fork-like structures within the stripes that originate from discontinuities in the phase of the recombined beam, forming striking features known as phase vortices.
Furthermore, from those interference patterns the intensity distribution in the exit plane of the channels is reconstructed, which is found to be in very good agreement to the actual channel design.
This study complements earlier work on two-dimensionally confined channels in silicon in straight and tapered geometries, and paves the way to realizing `X-ray optics on a chip'. Illumination of samples by the two beams could provide some interesting advantages for coherent imaging and opens up the possibility of a new form of nano-interferometer.
The authors envisage future development of their beamsplitter to create several daughter beams from the same parent beam, which would allow a single object to be imaged simultaneously by several beams, each from a different direction.
Dr. Jonathan Agbenyega | EurekAlert!
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
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