Simultaneous dual-species laser cooling using an optical frequency comb

TL;DR

This paper demonstrates the first successful simultaneous laser cooling of two rubidium isotopes using an optical frequency comb, showing potential for multi-species atomic experiments and applications.

Contribution

It introduces a novel method for dual-species laser cooling with a single frequency comb, maintaining individual cooling characteristics.

Findings

Both $^{85}$Rb and $^{87}$Rb are cooled to Doppler temperature simultaneously.

The cooling process does not interfere with each species' cooling characteristics.

The method enables potential multi-species atom interferometry and space applications.

Abstract

We demonstrate 1D simultaneous laser cooling of $^{87}$Rb and $^{85}$Rb atoms using an optical frequency comb. By adjusting the pulse repetition frequency and the offset frequency, the frequency comb spectrum is tuned to ensure that two distinct frequency comb modes are simultaneously red-detuned from the cooling transitions, one mode for each species. Starting from a pre-cooled cloud of $^{85,87}$Rb atoms at above-Doppler temperatures, we show simultaneous cooling of both species down to the Doppler temperature using two counter-propagating $\sigma$$^{+}$/$\sigma$$^{-}$-polarized beams from the frequency comb. The results indicate that simultaneous dual-species frequency comb cooling does not affect the cooling characteristics of individual atomic species. The results of this work imply that several atomic species could be cooled simultaneously using a single frequency comb source. This comb-based multi-channel laser cooling could bring significant advances in multi-species atom interferometers for space applications and in the study of multi-species interactions.