Authors: George Rajna
In analogy to the amplification of light in a laser, vibrations of a semiconductor crystal, so-called phonons, were enhanced by interaction with an electron current.  University of Central Florida researchers have developed a way to control the speed of light. Not only can they speed up a pulse of light and slow it down, they can also make it travel backward.  X-ray free-electron lasers (XFELs) produce incredibly powerful beams of light that enable unprecedented studies of the ultrafast motions of atoms in matter.  Using ultrashort laser pulses lasting a few picoseconds (trillionths of a second), Lawrence Livermore National Laboratory (LLNL) researchers have discovered an efficient mechanism for laser ablation (material removal) that could help pave the way to the use of lower-energy, less costly lasers in many industrial laser processing applications.  Engineers at Ruhr-Universität Bochum have developed a novel concept for rapid data transfer via optical fibre cables.  Particles can exchange their spin, and in this way spin currents can be formed in a material.  Researchers have shown that certain superconductors-materials that carry electrical current with zero resistance at very low temperatures-can also carry currents of 'spin'.  The first known superconductor in which spin-3/2 quasiparticles form Cooper pairs has been created by physicists in the US and New Zealand.  Now a team of researchers from the University of Maryland (UMD) Department of Physics together with collaborators has seen exotic superconductivity that relies on highly unusual electron interactions.  A group of researchers from institutions in Korea and the United States has determined how to employ a type of electron microscopy to cause regions within an iron-based superconductor to flip between superconducting and non-superconducting states.  In new research, scientists at the University of Minnesota used a first-of-its-kind device to demonstrate a way to control the direction of the photocurrent without deploying an electric voltage. 
Comments: 39 Pages.
[v1] 2019-04-04 09:13:28
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