Category Physics

Coreless optical fibre: If a photonic crystal fibre is twisted, it does not require a core with a different refractive index to trap light at its centre. Credit: Science 2016/MPI for the Science of Light

Researchers have discovered a new mechanism for guiding light in photonic crystal fibre (PCF). PCF is a hair-thin glass fibre with a regular array of hollow channels running along its length. When helically twisted, this spiralling array of hollow channels acts on light rays in an analogous manner to the bending of light rays when they travel through the gravitationally curved space around a star, as described by the general theory of relativity.

Optical fibres act as pipes for light...

Illustration of a broadband terahertz amplifier based on a quantum cascade laser. It allows for an amplifier range of more than 1 THz and the generation of ultrashort light pulses with record pulse widths of 3 ps. Credit: Image courtesy of Vienna University of Technology, TU Vienna

A group from TU Wien and ETH Zurich have succeeded in their attempts to generate ultrashort terahertz light pulses. With lengths of just a few picoseconds, these pulses are ideally suited to spectroscopic applications and enable extremely precise frequency measurements to be taken. The unique properties of terahertz radiation mean it is of interest for a wide range of potential applications, including non-invasive medical imaging and the detection of hazardous substances...

A laser stylus writes on a small array of multifunction pixels made by dual-function LEDs than can both emit and respond to light. Credit: Image courtesy of Moonsub Shim, University of Illinois

Cellphones and other devices could soon be controlled with touchless gestures and charge themselves using ambient light, thanks to new LED arrays that can both emit and detect light. Made of tiny nanorods arrayed in a thin film, the LEDs could enable new interactive functions and multitasking devices. “These LEDs are the beginning of enabling displays to do something completely different, moving well beyond just displaying information to be much more interactive devices,” said Prof. Moonsub Shim. “That can become the basis for new and interesting designs for a lot of electronics...