KRISS reduces uncertainty in strontium frequency measurement by more than 50 times

Researchers at the Korea Research Institute of Standards and Science measured a strontium atomic transition with uncertainty of about 5 megahertz, more than 50 times lower than the previous reference. Published in Metrologia, the result supplies a more precise reference for lasers used to cool and trap atoms in clocks, sensors and neutral-atom quantum computers. A photonic grating chip directs laser light inside a vacuum, reducing vibration errors and simplifying an arrangement otherwise requiring multiple external mirrors. Two independent measurement methods agreed within their margins of error. Using the reference to help free devices from bulky external frequency references also depends on optical frequency synthesis technology still being developed.