Spatio-temporal Monte Carlo modeling of loading and decay dynamics in an optical dipole trap

TL;DR

This paper models the intra-trap dynamics of an optical dipole trap loaded from a magneto-optical trap using spatio-temporal Monte Carlo simulations, revealing dominant loss mechanisms under different conditions.

Contribution

It introduces a combined spatio-temporal Monte Carlo simulation approach to accurately estimate intra-trap loss parameters and atom-number evolution in an optical dipole trap.

Findings

Momentum-transfer elastic collisions dominate atom decay without MOT beams.

Radiative escape is the primary loss mechanism with MOT beams.

The simulation closely matches experimental atom-number evolution.

Abstract

Here, we present our studies on intra-trap dynamics of an optical dipole trap (ODT) loaded from a Magneto-optical trap (MOT) of $^{87}$Rb atoms. A spatio-temporal Monte Carlo (MC) simulation approach has been employed in conjunction with the semi-classical theory based calculations for estimation of various intra-trap two-body loss parameters in the ODT. The temporal MC method based on estimated parameters from spatial MC, gives a close estimation of the experimentally observed atom-number evolution in ODT. We also find that, the decay rate of atoms in an ODT is dominated by momentum-transfer elastic collisions in the absence of MOT beams. However, in presence of MOT beams, the radiative escape process is the dominant two-body loss mechanism in the trap, which surpasses the fine-structure changing and hyperfine changing collisional losses by nearly an order of magnitude.