More accurate navigation systems and improved wireless communications may not come from traditional electronics, but rather from atoms. Researchers at Penn State and the National Institute of Standards and Technology (NIST) have developed a new way to build tinier, smarter glass sensors filled with highly precise and stable atoms.
The team's work, published this week (June 18) in Nature Microsystems and Nanoengineering, centers on a manufacturable, silicon-free version of traditional bulky "vapor cells" - sealed chambers that contain cesium and rubidium atoms - that are commonly used in precision measurement systems, in a gas state. These atoms can act as highly precise sensors because, unlike manufactured components, atoms are fundamentally identical.
"Using atoms for sensing is advantageous because the physics of individual atoms is very well understood, and all the atoms are equal," said Daniel Lopez, co-lead author of the paper, Liang Professor of Electrical Engineering and Computer Science at Penn State and director of the Nanofabrication Lab at the Materials Research Institute (MRI). "That gives you a level of precision that's very hard to achieve with traditional microfabricated devices."
In the paper, the researchers reported that their cells - manufactured via a new method similar to the one used to make computer chips - remained stable over nearly three years of testing, showing that they maintained their internal vacuum and atomic performance over time.
"You need to have that gas inside the cavity for a decade so the sensor can work," Lopez said. "If you start leaking gas, your detector will stop working."
The research also demonstrated that the atoms in their glass cells can measure high-frequency electromagnetic signals, including millimeter-wave radiation, the kind of signal used in advanced communications and radar systems. This precision and sensitivity come from the use of atoms, Lopez said. He pointed to today's navigation devices, which typically rely on quartz crystals to keep time, as a comparison. These can vary from one to another, drift slightly and need frequent updates from GPS signals to stay accurate.
