Category Physics

Researchers demonstrate the first single-photon transistor using a semiconductor chip. They used a single photon, stored in a quantum memory, to toggle the state of other photons. Credit: E. Edwards/Joint Quantum Institute

Researchers have demonstrated the first single-photon transistor using a semiconductor chip. Transistors are tiny switches that form the bedrock of modern computing; billions of them route electrical signals around inside a smartphone, for instance. Quantum computers will need analogous hardware to manipulate quantum information. But the design constraints for this new technology are stringent, and today’s most advanced processors can’t be repurposed as quantum devices. That’s because qubits, have to follow different rules laid out by quantum physics.

Scientists can use ...

At left, different patterns of slices through a thin metal foil, are made by a focused ion beam. These patterns cause the metal to fold up into predetermined shapes, which can be used for such purposes as modifying a beam of light.
Credit: Courtesy of the researchers

Folding and cutting thin metal films could enable microchip-based 3D optical devices. Nanokirigami has taken off as a field of research in the last few years; the approach is based on the ancient arts of origami (making 3D shapes by folding paper) and kirigami (which allows cutting as well as folding) but applied to flat materials at the nanoscale, measured in billionths of a meter.

Now, researchers at MIT and in China have for the first time applied this approach to the creation of nanodevices to manipulate light, potentially...

Energy landscapes of a molecule during a light-driven chemical reaction. Like a golf ball rolling on a curved putting green, the molecule can follow reaction paths on these surfaces. Credit: Greg Stewart/SLAC National Accelerator Laboratory

An extremely fast “electron camera” at the Department of Energy’s SLAC National Accelerator Laboratory has produced the most detailed atomic movie of the decisive point where molecules hit by light can either stay intact or break apart. The results could lead to a better understanding of how molecules respond to light in processes that are crucial for life, like photosynthesis and vision, or that are potentially harmful, such as DNA damage from ultraviolet light.

In the study, researchers looked at a gas whose molecules have 5 atoms each...

Joule, Sun et al.: “Heat-insulating multifunctional semitransparent polymer solar cells” https://www.cell.com/joule/fulltext/S2542-4351(18)30242-3

Environmentally friendly building trends have boosted the popularity of window coatings that keep heating and cooling costs down by blocking out unneeded parts of sunlight. They have also inspired scientists and engineers to create thin, see-through solar cells to turn windows into miniature electricity generators. Researchers in China have gone a step further and combined these two functions into one window-compatible material that could double the energy efficiency of an average household. Their work appears July 3 in the journal Joule.

“Building-integrated photovoltaics are a great example of a market where silicon photovoltaics, despite thei...