Two-photon optical frequency reference with active ac Stark shift cancellation

TL;DR

This paper proposes a two-photon optical frequency reference with active ac Stark shift cancellation, aiming to improve stability by using two laser fields and demonstrating the method on rubidium atoms.

Contribution

It introduces a novel approach for ac Stark shift cancellation in two-photon optical references, enhancing stability over conventional methods.

Findings

Active ac Stark shift cancellation demonstrated in rubidium transition

Potential for improved short-term stability due to higher signal-to-noise ratio

Enhanced long-term stability through active shift cancellation

Abstract

An optical reference based on a two-photon optical transition with ac Stark shift cancellation is proposed. The reference uses two interrogating laser fields at different frequencies. Compared to conventional optical two-photon references, the new approach offers the possibility for improved short-term stability resulting from a higher signal-to-noise and improved long-term stability due to active ac Stark shift cancellation. We demonstrate the ac Stark shift cancellation method on the $5s\,{^2S}_{1/2} \rightarrow 5d\,{^2D}_{5/2}$ two-photon transition in $^{87}$Rb.