Large photon number extraction from individual atoms trapped in an optical lattice

TL;DR

This paper models polarization gradient cooling of atoms in optical lattices to enable high photon collection from individual atoms, crucial for atom-by-atom quantum gas characterization, showing that background gas collisions limit atom lifetime.

Contribution

It introduces a hybrid Monte Carlo and master equation model for three-dimensional polarization gradient cooling in optical lattices, predicting conditions for high photon yield and minimal atom loss.

Findings

Atoms can emit up to 10^8 photons before loss

Background gas collisions dominate atom lifetime

Optimal parameters extend atom fluorescence lifetime

Abstract

The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined in a short-period optical lattice to measure the position of individual atoms in the sample. A crucial condition for the measurements is that atomic hopping between lattice sites must be strongly suppressed despite substantial photon recoil heating. This article models three-dimensional polarization gradient cooling of atoms trapped within a far-detuned optical lattice. The atomic dynamics are simulated using a hybrid Monte Carlo and master equation analysis in order to predict the frequency of processes which give rise to degradation or loss of the fluorescent signal during measurements. It is shown, consistent with the experimental results, that there exists a wide parameter range in which the lifetime of strongly-fluorescing isolated lattice-trapped atoms is limited by background gas collisions rather than radiative processes. In these cases the total number of scattered photons can be as large as 10^8 per atom. The performance of the technique is related to relevant experimental parameters.