Auto-Balanced Ramsey Spectroscopy

TL;DR

This paper introduces an auto-balanced Ramsey spectroscopy method that actively cancels interrogation-induced shifts, enabling highly accurate atomic clock measurements without error from common perturbations.

Contribution

The authors develop a universal, perturbation-immune Ramsey spectroscopy technique that balances responses from unequal probe cycles to eliminate systematic shifts.

Findings

Successfully demonstrated on $^{171}$Yb$^{+}$ optical clock transition.

Eliminates light shifts, phase chirps, and Zeeman shifts.

Achieves frequency accuracy below 10^{-18}.

Abstract

We devise a perturbation-immune version of Ramsey's method of separated oscillatory fields. Spectroscopy of an atomic clock transition without compromising the clock's accuracy is accomplished by actively balancing the spectroscopic responses from phase-congruent Ramsey probe cycles of unequal durations. Our simple and universal approach eliminates a wide variety of interrogation-induced line shifts often encountered in high precision spectroscopy, among them, in particular, light shifts, phase chirps, and transient Zeeman shifts. We experimentally demonstrate auto-balanced Ramsey spectroscopy on the light shift prone $^{171}$Yb$^{+}$ electric octupole optical clock transition and show that interrogation defects are not turned into clock errors. This opens up frequency accuracy perspectives below the $10^{-18}$ level for the Yb$^{+}$ system and for other types of optical clocks.