Researchers at the National Institute of Standards and Technology (NIST) have created a chip on which laser light interacts with a tiny cloud of atoms to serve as a miniature toolkit for measuring important quantities such as length with quantum precision. The design could be mass-produced with existing technology.
Above – NIST’s prototype chip for measuring important quantities such as length with quantum precision. The device works by using a laser to probe atoms to generate infrared light at a precise wavelength. The NIST chip packs a tiny cloud of atoms and structures for guiding light waves into less than 1 square centimeter. The atoms are contained in a vapor cell—the square window on top of the chip, which is surrounded by black epoxy holding a fiber-optic array. The penny is a scale reference. Credit: Hummon/NIST
NIST’s prototype chip was used to generate infrared light at a wavelength of 780 nanometers, precisely enough to be used as a length reference for calibrating other instruments. The NIST chip packs the atom cloud and structures for guiding light waves into less than 1 square centimeter, about one ten-thousandth of the volume of other compact devices offering similar measurement precision.
The NIST chip might be used, for example, to calibrate length measurement instruments. The international length standard is based on the speed of light, equivalent to the wavelength of light multiplied by its frequency.
But more importantly, the new chip shows that lasers and atomic vapor cells could potentially be mass- produced together like semiconductors, using silicon materials and traditional chip-manufacturing techniques, instead of the current manual assembly of bulky optics and blown-glass vapor cells, NIST group leader John Kitching said. This advance could apply to many NIST instruments, from atomic clocks to magnetic sensors and gas spectrometers.