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Superfast light source made from artificial atom

A new method to create light while retaining the energy using Q-Dot technology.

All light sources work by absorbing energy – for example, from an electric current – and emit energy as light. But the energy can also be lost as heat and it is therefore important that the light sources emit the light as quickly as possible, before the energy is lost as heat. Superfast light sources can be used, for example, in laser lights, LED lights and in single-photon light sources for quantum technology. New research results from the Niels Bohr Institute show that light sources can be made much faster by using a principle that was predicted theoretically in 1954. The results are published in the scientific journal, Physical Review Letters.

Researchers at the Niels Bohr Institute are working with quantum dots, which are a kind of artificial atom that can be incorporated into optical chips. In a quantum dot, an electron can be excited (i.e. jump up), for example, by shining a light on it with a laser and the electron leaves a ‘hole’. The stronger the interaction between light and matter, the faster the electron decays back into the hole and the faster the light is emitted.

But the interaction between light and matter is naturally very weak and it makes the light sources very slow to emit light and this can reduce energy efficiency. Already in 1954, the physicist Robert Dicke predicted that the interaction between light and matter could be increased by having a number of atoms that ‘share’ the excited state in a quantum superposition.

Shoot the Blighter! Anti-drone ‘death ray’ may be installed after Heathrow plane collision (VIDEO)

A military-grade drone-killing ‘death ray’ that can reportedly destroy unmanned aerial vehicles (UAV) from up to 6 miles away could soon be in use in UK airports following a suspected collision with a passenger jet at Heathrow last Thursday.

The collision, which led to a drone ban over London during US President Barrack Obama’s UK visit, has forced authorities to consider more aggressive countermeasures.

Media unveils Russian battle robots for future warfare

It Looks exactly like Boston Dynamics cancelled Big Dog project, and it is armed with some kind of a Light machine gun. I said that cancelling the Big Dog project was a mistake. We Can’t Allow a robotics gap between the US and Russian/Chinese forces. And, the other side has absolutely no hang ups about arming their robots.

In his twitter page Igor Korotchenko, editor-in-chief of the Russian magazine Natsionalnaya Oborona (National Defense) has published the first-ever photos of Russia’s advanced biomorphic combat robot.

The alleged advanced biomorphic combat robot of Russia will move like a four legged animal and it will be equipped with a machine gun and guided antitank missiles, as suggested by the photos.

According to Sputnik, photos appeared after media reports said that Russia to create a state-of-the-art biomorphic combat robot which will walk on four “legs” and will be armed with a machine gun and guided antitank missiles.

Flipping a chemical switch helps perovskite solar cells beat the heat

Thin films of crystalline materials called perovskites provide a promising new way of making inexpensive and efficient solar cells. Now, an international team of researchers has shown a way of flipping a chemical switch that converts one type of perovskite into another—a type that has better thermal stability and is a better light absorber.

The study, by researchers from Brown University, the National Renewable Energy Laboratory (NREL) and the Chinese Academy of Sciences’ Qingdao Institute of Bioenergy and Bioprocess Technology published in the Journal of the American Chemical Society, could be one more step toward bringing to the mass market.

“We’ve demonstrated a new procedure for making solar cells that can be more stable at moderate temperatures than the perovskite solar cells that most people are making currently,” said Nitin Padture, professor in Brown’s School of Engineering, director of Brown’s Institute for Molecular and Nanoscale Innovation, and the senior co-author of the new paper. “The technique is simple and has the potential to be scaled up, which overcomes a real bottleneck in perovskite research at the moment.”

Physicists detect the enigmatic spin momentum of light

Ever since Kepler’s observation in the 17th century that sunlight is one of the reasons that the tails of comets to always face away from the sun, it has been understood that light exerts pressure in the direction it propagates. Radiation pressure is produced by the momentum carried by light, and it plays a crucial role in a variety of systems, from atomic to astronomical scales.

In a recent theoretical paper, a group from the RIKEN Center for Emergent Matter Science in Japan showed that density in non-uniform optical fields has an unusual component, which is orthogonal to the propagation direction of and is proportional to the optical spin, which means the degree of circular polarization. They predicted that this spin momentum would produce a transverse spin-dependent optical force, a few orders of magnitude weaker than the usual .

Now, based on the theoretical work, a group from RIKEN, the University of Bristol, and other institutions have used an extremely precise technique to experimentally verify that light does in fact exert the extraordinary perpendicular force, which is determined by the polarization of the light. The research has been published in Nature Physics.