Sympathetic cooling of OH- ions using ultracold Rb atoms in a dark SPOT

TL;DR

This paper presents a novel hybrid trap design combining an octupole rf-trap and a dark SPOT to facilitate efficient sympathetic cooling of OH- ions with ultracold Rb atoms, promising high collision rates and reduced inelastic collisions.

Contribution

The paper introduces a new hybrid atom-ion trap design that enhances collision rates and suppresses inelastic collisions for sympathetic cooling of ions.

Findings

Numerical simulations predict feasible cooling of ions.

High collision rates due to increased atom density in dark SPOT.

Suppression of inelastic collisions with ground-state atoms.

Abstract

We are developing a new hybrid atom-ion trap to study the interaction of ultracold rubidium atoms with mass-selected OH- molecules. The ions are trapped inside an octupole rf-trap made of thin wires instead of the commonly used rods. This ensures good optical access to the center of the trap where the ions can be overlapped with laser cooled rubidium atoms stored in a dark spontaneous force optical trap (dark SPOT). This setup provides high collision rates since the density in a dark SPOT is about one order of magnitude higher than in a standard magneto-optical trap. Further, inelastic collisions with excited atoms are suppressed since almost all atoms are in the ground state. Numerical simulations of our setup using SIMION predict that cooling of the ions is feasible.