Visible light and X-rays are different types of radiation. Visible light, for example, doesn’t penetrate the human body, whereas X-rays are absorbed weakly and can be used in medical imaging.
Similar differences exist at very high light intensities, which make X-rays potentially useful in materials science, but this area—referred to as ‘nonlinear optics’—remains largely unexplored. Now, researchers from the RIKEN SPring-8 Center in Harima have taken the first step in establishing a more systematic approach to studying nonlinear X-ray effects1.
The team investigated the so-called parametric down-conversion of a single X-ray photon that splits into two separate photons, whose combined energy equals the original photon’s energy. This effect was studied in a diamond crystal, which provided the medium for this process to occur. The necessary high intensity X-ray radiation came from the SPring-8 synchrotron, which is ideally suited for the task, according to Kenji Tamasaku from the research team. “It delivers some of the world’s brightest X-rays.”
However, a competing process can occur in addition to the down-conversion: the creation of only one X-ray photon and the simultaneous excitation of one of the material’s electron to another state from the remainder of the original energy. An observer cannot distinguish which of these processes actually occurred in the material to produce outcoming photons of the same energy, which means that there is a quantum mechanical interference between both processes. This is known as the Fano effect.
Tamasaku and colleagues studied the Fano effect for a range of parameters including X-ray photon energy. Based on theoretical modeling of a large dataset available from their experiments, they quantified efficiency of the nonlinear down-conversion process of X-rays for the first time. The possibility of this achievement had long been doubtful, as it requires not only a careful experimental calibration, but also very high X-ray intensities that are available at SPring-8.
The quantitative results for the nonlinear optical parameters of the down-conversion process are convincing and largely in line with theoretical expectations, even though some of the features observed remain poorly understood.
Nevertheless, Tamasaku is confident that “these results represent the first firm base from which to venture into the frontier of X-ray nonlinear optics.” In particular, he is hopeful that the completion of a new X-ray laser called X-ray Free Electron Laser (XFEL) at SPring-8 next year will significantly expand the potential for the study of these non-linear optical effects.
The corresponding author for this highlight is based at the Coherent X-Ray Optics Laboratory, RIKEN SPring-8 Center
Saeko Okada | Research asia research news
SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University
Molecule flash mob
19.01.2017 | Technische Universität Wien
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences