Optical repumping and atom number balancing in a two-color MOT

TL;DR

This paper introduces a novel two-color MOT scheme for $^{88}$Sr atoms that enhances atom trapping efficiency and allows for atom number balancing, enabling low-temperature operation and continuous atomic beam production.

Contribution

It demonstrates a new repumping method combined with a green MOT that significantly increases atom numbers and enables control over atom population balance.

Findings

Green MOT traps 10 times more atoms than using green transition solely as a repump.

Atom numbers in the two-color MOT can be balanced through experimental parameters.

The scheme is suitable for low-temperature and continuous atomic beam applications.

Abstract

We study a novel repumping transition for $^{88}$Sr atoms trapped in a 'blue' magneto-optical trap. We show that, while the repumping efficiency is about three orders of magnitude smaller than for traditional schemes, it is sufficient for recycling all atoms, provided the repumping laser beams are arranged to form a 'green' magneto- optical trap (MOT) helping to cool and confine the atoms and preventing their loss. Our main findings are: (i) that the green MOT configuration is able to trap 10 times more atoms in the blue MOT than using the green transition merely as a repump, and (ii) that the atom numbers in the two-color MOT can be balanced through experimental control parameters. The interest of this scheme lies in its capability of reaching low temperature and its suitability for continuous atomic beam generation.