Modified hyper-Ramsey methods for the elimination of probe shifts in optical clocks

TL;DR

This paper introduces a modified hyper-Ramsey spectroscopy technique for optical clocks that effectively eliminates probe-induced frequency shifts, enhancing measurement accuracy and robustness.

Contribution

The authors develop a novel pulse sequence with tailored phases, frequencies, and durations that cancels probe shifts in optical clocks, demonstrated experimentally with strontium atoms.

Findings

Achieved suppression of a 2×10⁻¹³ probe Stark shift to below 10⁻¹⁶

Demonstrated robustness against large errors in shift compensation

Validated the method using the $^{88}$Sr transition in experiments

Abstract

We develop a method of modified hyper-Ramsey spectroscopy in optical clocks, achieving complete immunity to the frequency shifts induced by the probing fields themselves. Using particular pulse sequences with tailored phases, frequencies, and durations, we can derive an error signal centered exactly at the unperturbed atomic resonance with a steep discriminant which is robust against variations in the probe shift. We experimentally investigate the scheme using the magnetically-induced $^1$S$_0- ^3$P$_0$ transition in $^{88}$Sr, demonstrating automatic suppression of a sizeable \num{2e-13} probe Stark shift to below \num{1e-16} even with very large errors in shift compensation.