June 2016
Spotlight Summary by Tetsuya Ido
Measuring absolute frequencies beyond the GPS limit via long-haul optical frequency dissemination
SI-traceable measurement of optical frequencies is no longer the privilege of national metrological institutes. In this recently published article in Optics Express by Clivati et al., high-speed optical frequency measurement based on the remote SI second is reported by an Italian team comprising of a university and a metrological institute. The university laboratory is in Florence, whereas the metrological partner is in Torino, which is located 250 km away at the south foot of Alps. What connected these two cities was a noise-compensated optical fiber, providing an accurate frequency reference at the university with a short-term stability of 10-14 level. In the case of the state-of-the-art GPS disciplined oscillator it takes more than 104 s of signal integration to reach this level. The measurement using the remote reference demonstrated here has reduced the uncertainty of the 173Yb 1S0-3P0 transition frequency by two orders of magnitude. High resolution measurement enabled by an accurate reference will become a powerful tool not only for metrologists but also for some quantum physicists. Stable frequency reference may reveal subtle phenomena that have been hidden behind noise.
You must log in to add comments.
Add Comment
You must log in to add comments.
Article Information
Measuring absolute frequencies beyond the GPS limit via long-haul optical frequency dissemination
Cecilia Clivati, Giacomo Cappellini, Lorenzo F. Livi, Francesco Poggiali, Mario Siciliani de Cumis, Marco Mancini, Guido Pagano, Matteo Frittelli, Alberto Mura, Giovanni A. Costanzo, Filippo Levi, Davide Calonico, Leonardo Fallani, Jacopo Catani, and Massimo Inguscio
Opt. Express 24(11) 11865-11875 (2016) View: HTML | PDF