# Three dimensional cooling and trapping with a narrow line

## TL;DR

This paper investigates the efficiency and physical characteristics of a strontium magneto-optical trap using a narrow intercombination line, highlighting the effects of gravity and magnetic fields on cooling and trapping.

## Contribution

It provides a systematic analysis of loading efficiency and the influence of gravity in a narrow-line MOT, supported by a simple model and experimental data.

## Key findings

- Optimal loading efficiency depends on laser detuning and magnetic field.
- Gravity significantly affects the trap's position, size, and temperature.
- Cooling and trapping can occur with high magnetic bias at large detuning.

## Abstract

The intercombination line of Strontium at 689nm is successfully used in laser cooling to reach the photon recoil limit with Doppler cooling in a magneto-optical traps (MOT). In this paper we present a systematic study of the loading efficiency of such a MOT. Comparing the experimental results to a simple model allows us to discuss the actual limitation of our apparatus. We also study in detail the final MOT regime emphasizing the role of gravity on the position, size and temperature along the vertical and horizontal directions. At large laser detuning, one finds an unusual situation where cooling and trapping occur in the presence of a high bias magnetic field.