NIST is developing a high-accuracy optical frequency reference using a single trapped Sr+ ion. The goal is to provide long-term frequency stability to the timescale’s maser ensemble, with measurements made several times per week. The 674 nm clock transition has been studied at several NMI’s at the 10-17 level, and advances in light source technology may allow operation with just two lasers. The project aims to bridge continuously operated microwave fountain references and lower-uptime experimental optical frequency references.
Source: https://www.nist.gov/programs-projects/trapped-sr-ion-clock-secondary-realization-si-second
Keywords: precision, optical frequency, spectroscopy
