Single-frequency inverted Doppler-free resonance as a platform for chip-scale optical clock

TL;DR

This paper demonstrates a high-quality inverted Doppler-free resonance in alkali-metal atoms using a single-frequency regime, enabling simpler and compact optical clocks with stability comparable to dual-frequency methods.

Contribution

It introduces a novel single-frequency approach for Doppler-free resonance in alkali-metal atoms, simplifying optical clock design without sacrificing stability.

Findings

Resonance contrast-to-width ratio is similar in single- and dual-frequency regimes.

Achieved short-term frequency stability of 3×10^(-13) at 1 second.

Single-frequency regime simplifies optical clock modules.

Abstract

We report on the possibility to obtain a high-quality inverted Doppler-free resonance in D1 line of alkali-metal atoms in the single-frequency regime. The counter-propagating optical fields with linear and mutually orthogonal polarizations and the transition Fg=I+1/2 --> Fe=I-1/2 are proposed to the use. We establish the best possible nuclear spin value and the corresponding atomic isotope for this regime. Our experiment demonstrates that the resonance contrast-to-width ratio in the single-frequency regime is practically the same as in the dual-frequency regime, which simplifies the optical module to be used in compact optical clocks. The achieved short-term frequency stability is 3*10^(-13) at 1 s, which is comparable to results that can be obtained with the dual-frequency technique.