Stochastic laser cooling enabled by many body effects

TL;DR

This paper introduces a new laser cooling method leveraging many body effects and collective light-matter interactions, enabling efficient cooling at higher densities than traditional techniques.

Contribution

The authors propose a stochastic laser cooling mechanism based on many body effects, expanding applicability to higher density atomic and molecular ensembles.

Findings

Cooling rates up to 100 K/s for dense ^87Rb ensembles

Enhanced cooling rates up to 600 K/s with a tuning laser

Effective at densities as high as 10^14 cm^-3

Abstract

A novel laser cooling mechanism based on many body effects is presented. The method can be applicable for cooling a large class of atoms and molecules in higher density than commonly excepted by existing methods. The cooling mechanism relies on the collective encounters of particle and light. Stochastic events between the particles and photons as well as a collective effect give rise to energy transfer between these media. Such mechanism relies on multiple light-matter encounters, therefore requiring a sufficient particle density, $\rho \sim 10^{14} \text{cm}^{-3}$. This is an advantage for experiments where high phase space density is required. A second tuning laser can be added increasing the applicability to many types of atoms and molecules. This tuning laser changes the inter-particle potential by inducing an AC stark effect. As a result the required trapping density can be reduced down to $\rho \sim 10^6 \text{cm}^{-3}$. Simulations of phase space distributions were performed comparing different particle densities, trap potentials and light field intensity profiles. The modelling shows efficient cooling rates up to $~10^{2} \text{K/s}$ for a dense ensemble of $~^{87}$Rb atoms, and cooling rates up to $~6\cdot 10^{2} \text{K/s}$ when adding an additional tuning source.