# Light assisted collisions in ultra-cold Tm atoms

## TL;DR

This paper investigates light assisted collisions in ultra-cold Tm atoms within a magneto optical trap, revealing the effects of radiation trapping and quantifying binary loss rates near a specific cooling transition.

## Contribution

First study of light assisted collisions in Tm atoms, measuring loss rates and separating effects of radiation trapping and collisions in a MOT.

## Key findings

- Binary loss rate constant up to 10^{-9} cm^3/s
- Upper bound on branching ratio at 0.8×10^{-6}
- Radiation trapping significantly influences trap dynamics

## Abstract

We studied light assisted collisions of Tm atoms in a magneto optical trap (MOT) for the first time, working on a weak cooling transition at 530.7 nm $(4f^{13}(^2F^0)6s^2,J=7/2,F=4$ to $4f^{12}(^3H_6)5d_{5/2}6s^2,J=9/2,F=5)$. We observed a strong influence from radiation trapping and light assisted collisions on the dynamics of this trap. We carefully separated these two contributions and measured the binary loss rate constant at different laser powers and detuning frequencies near the cooling transition. Analyzing losses from the MOT, we found the light assisted inelastic binary loss rate constant to reach values of up to $\beta=10^{-9}$ cm$^3$/s and gave the upper bound on a branching ratio $k<0.8\times 10^{-6}$ for the 530.7 nm transition.

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Source: https://tomesphere.com/paper/1701.07924