JILA Science Seminar - Hiutat Yang

About this event

Event Title : A Prototype of a Commercial Optical Lattice Clock

Abstract: As microwave atomic clocks have advanced, a wide range of practical products have been developed for timekeeping and synchronization. Optical clocks have surpassed microwave primary frequency standards in accuracy, opening new applications such as relativistic geodesy. Realizing these applications requires practical instruments capable of delivering reliable frequency performance in field environments. We present a 250-litter strontium optical lattice clock prototype developed in collaboration with industry.

We briefly describe the system architecture and evaluate its frequency performance, focusing on the background-gas collision shift, which, to our knowledge, has been experimentally characterized only once before. We independently measured the shift by increasing the background-gas pressure under conditions where H₂ was the dominant residual species. The result was consistent with the previously reported value within the stated uncertainties. The discrepancy between the experimental results and theoretical estimates may arise from difficulties in accounting for J-mixing in the intermolecular potential calculations. We also discuss the challenge of demonstrating reproducibility among independent optical clocks at the 10-18 level.

Finally, we report recent field tests toward relativistic geodesy at Mt. Fuji, Japan's highest mountain, in collaboration with the University of Western Australia. A free-space optical

link using CW lasers was established and phase-locked for 20–30 minutes during brief clear-sky windows.