Category Physics

One of NIST’s ytterbium lattice atomic clocks. NIST physicists combined two of these experimental clocks to make the world’s most stable single atomic clock. The image is a stacked composite of about 10 photos in which an index card was positioned in front of the lasers to reveal the laser beam paths. Credit: N. Phillips/NIST

What could be better than a world-leading atomic clock? 2 clocks in 1. Physicists NIST have combined two experimental atomic clocks based on ytterbium atoms to set yet another world record for clock stability. Stability can be thought of as how precisely the duration of each clock tick matches every other tick that comes before and after...

This image shows theoretical (right) and experimental (left) iso-frequency contours of a photonic crystal slabs superimposed on each other. Credit: Massachusetts Institute of Technology

A new technique developed by MIT researchers reveals the inner details of photonic crystals, synthetic materials whose exotic optical properties are the subject of widespread research. Photonic crystals are generally made by drilling millions of closely spaced, minuscule holes in a slab of transparent material, using variations of microchip-fabrication methods...

Researchers have discovered how to control molecules attached to graphene, paving the way for tiny biological sensors and devices to hold information.

Researchers have discovered how to control molecules attached to graphene, paving the way for tiny biological sensors and devices to hold information. Because of its unique electrical conductivity, graphene has the potential to be a base for electronic devices that are only nanometres in size. In order to tune sheets of graphene to be useful in different situations, other organic molecules are attached to the sheet, and these molecules must interact with the graphene sheet in predictable ways.

Eg. if the electric charge of molecules could be controlled, then they could be used as molecular ‘switches’...

Bottom: Platinum atoms attached to layers of lithium cobalt oxide contract when electricity is applied, boosting platinum catalytic efficiency by 90 percent. Top: Removing electrons separates the atoms and lowers efficiency by 40 percent. (1 Ångstrom = 0.1 nanometer) (Image credit: Haotian Wang)

A nanosize squeeze can significantly boost the performance of platinum catalysts that help generate energy in fuel cells, according to a new study by Stanford scientists. The team bonded a platinum catalyst to a thin material that expands and contracts as electrons move in and out, and found that squeezing the platinum a fraction of a nanometer nearly doubled its catalytic activity.

“In this study, we present a new way to fine...