Dual optical frequency combs with ultra-low relative phase jitters from 550 nm to 1020 nm for precision spectroscopy

TL;DR

This paper demonstrates ultra-low phase jitters in dual optical frequency combs across 550 nm to 1020 nm, enabling high-precision spectroscopy and stable optical frequency referencing over a broad spectrum.

Contribution

It introduces a method to achieve ultra-low relative phase jitters in dual combs over a wide spectrum by phase-locking to a Sr optical lattice clock laser.

Findings

Relative phase jitters below 1 rad over 8.3 mHz to 200 kHz range

Relative linewidth below 8.3 mHz across 550 nm to 1020 nm

Enables ultrahigh-precision dual-comb spectroscopy

Abstract

Here, ultra-low relative phase jitters over a wide optical spectrum were achieved for dual Ti:Sapphire optical frequency combs. The two optical frequency combs were independently phase-locked to a Sr optical lattice clock laser delivered through a commercial optical fiber network. We confirmed that the relative phase jitters between the two combs integrated from 8.3 mHz to 200 kHz were below 1 rad, corresponding to a relative linewidth of below 8.3 mHz, over the entire wavelength of the optical frequency combs ranging from 550 nm to 1020 nm. Our work paves the way for ultrahigh-precision dual-comb spectroscopy covering a wide optical spectral range with a simple setup, and provides an absolute optical frequency reference with great stability over a wide range of wavelengths.