loading page

Optical Frequency Transfer for Geopotential Difference Measurements via a Flying Drone
  • +5
  • Benjamin Dix-Matthews ,
  • David Gozzard ,
  • Shane Walsh ,
  • Ayden McCann ,
  • Skevos Karpathakis ,
  • Alex Frost ,
  • Charles Gravestock ,
  • Sascha Schediwy
Benjamin Dix-Matthews
Author Profile
David Gozzard
University of Western Australia

Corresponding Author:[email protected]

Author Profile
Shane Walsh
Author Profile
Ayden McCann
Author Profile
Skevos Karpathakis
Author Profile
Alex Frost
Author Profile
Charles Gravestock
Author Profile
Sascha Schediwy
Author Profile


Geopotential and orthometric height differences between distant points can be measured via timescale comparisons between atomic clocks. Modern optical atomic clocks have residual instabilities on the order of 10^-18}, allowing height differences of around 1 cm to be measured. Frequency transfer via free-space optical links will be needed for measurements where linking the clocks via optical fiber is not possible, but requires line of sight between the clock locations, which is not always practical due to local terrain or over long distances. We present an active optical terminal, phase stabilization system, and phase compensation processing method robust enough to enable optical frequency transfer via a flying drone, greatly increasing the flexibility of free-space optical clock comparisons. We demonstrate a residual instability of 2.5x10^-18 after 3 s of integration, corresponding to a height difference of 2.3 cm, suitable for applications in geodesy, geology, and fundamental physics experiments.
24 Apr 2023Published in Optics Express volume 31 issue 9 on pages 15075. 10.1364/OE.483767