Optimizing the efficiency of evaporative cooling in optical dipole traps

TL;DR

This paper combines computational modeling and experimental validation to optimize evaporative cooling in optical dipole traps, leading to highly efficient Bose-Einstein condensate production with minimal initial atoms.

Contribution

It introduces a kinetic model-based strategy for optimizing evaporative cooling parameters and demonstrates its effectiveness through experimental implementation.

Findings

Achieved an evaporation efficiency of 4.0.

Produced Bose-Einstein condensates with 2×10^4 atoms.

Started from 5×10^5 atoms in the trap.

Abstract

We present a combined computational and experimental study to optimize the efficiency of evaporative cooling for atoms in optical dipole traps. By employing a kinetic model of evaporation, we provide a strategy for determining the optimal relation between atom temperature, trap depth, and average trap frequency during evaporation given experimental initial conditions. We then experimentally implement a highly efficient evaporation process in an optical dipole trap, showing excellent agreement between the theory and experiment. This method has allowed the creation of pure Bose-Einstein condensates of $^{87}$Rb with 2$\times 10^4$ atoms starting from only $5\times 10^5$ atoms initially loaded in the optical dipole trap, achieving an evaporation efficiency, $\gamma_{eff}$, of 4.0 during evaporation.