Category Physics

Scientists inserted helium ions into a thin crystalline film (gold) to controllably increase the out-of-plane crystal dimension, while the underlying substrate (black) fixed the in-plane directions. The red balloon represents one helium atom in the crystalline lattice. Credit: Oak Ridge National Laboratory

With just a bit of helium, the lighter-than-air element that makes balloons float, scientists have done what was once thought impossible – they stretched a crystal lattice in just one dimension, allowing them to tune the structure’s electronic and magnetic properties. To achieve this elongation, scientists devised a new method called “strain doping.” Scientists implant helium ions into a crystal. The helium gently pushes up against the structure, like a balloon under a sheet...

This image shows trajectory of (a) position and (b) orientation of pliers under repetitive laser irradiation without tracking. Grey lines indicate the projections of the trajectory in the respective coordinate planes. Credit: © the authors doi: 10.1117/1.OE.56.1.011007

Space debris from completed missions – inactive satellites, lens covers, fragments from spaceship disengagements – pose a serious and ongoing threat to active communication and navigation satellites used by billions of people on Earth. An article published by SPIE, the international society for optics and photonics, in Optical Engineering describes a new approach whereby debris orbiting in space could be pushed into Earth’s atmosphere by laser impulses, causing it to burn up.

High definition model of a set of pliers taken...

Some measurements of entanglement violate monogamy, yet are geometrically faithful; others are monogamous but not faithful. Credit: Lancien et al. ©2016 American Physical Society

As expected, “monogamous” and “faithful” mean something a little different in the quantum world than they do in everyday language. When quantified by standard means, entanglement cannot be both monogamous and faithful at the same time. The results may be relevant when assessing the security of quantum cryptographic schemes, which rely on the monogamy of entanglement, and may also help to better understand the long-standing “firewall debate” related to the behavior of black holes.

Monogamy is considered to be a defining property of entanglement. Eg...

A plasmonic detector that is directly coupled to a silicon optical waveguide and smaller than one micrometer was developed by KIT. Credit: Graphics: KIT

Data traffic is growing worldwide. Glass-fiber cables transmit information over long distances at the speed of light. These optical signals have to be converted into electrical signals for processing in the computer. KIT researchers have now developed a novel type of photodetector that needs far less space than conventional ones. The component has a base area of <1 millionth sq mm without data transmission rate being affected adversely.

The newly developed photodetectors, the smallest photodetectors worldwide for optical data transmission, can be used for integrated optical circuits that significantly enhance the performance of optical com...