High-Precision Spectroscopy with Counter-Propagating Femtosecond Pulses

TL;DR

This paper demonstrates a high-precision spectroscopy technique using counter-propagating femtosecond pulses that significantly improves measurement accuracy of atomic transitions by eliminating Doppler broadening.

Contribution

The authors introduce a simple pulse shaping method to eliminate Doppler background, enabling ultra-precise measurement of rubidium two-photon transitions with uncertainties below 10^{-11}.

Findings

Achieved measurement uncertainties below 10^{-11}.

Successfully eliminated Doppler broadening effects.

Improved precision by an order of magnitude over previous methods.

Abstract

An experimental realization of high-precision direct frequency comb spectroscopy using counter-propagating femtosecond pulses on two-photon atomic transitions is presented. Doppler broadened background signal, hampering precision spectroscopy with ultrashort pulses, is effectively eliminated with a simple pulse shaping method. As a result, all four 5S-7S two-photon transitions in a rubidium vapor are determined with both statistical and systematic uncertainties below 10$^{-11}$, which is an order of magnitude better than previous experiments on these transitions.