Light-induced atomic desorption of lithium

TL;DR

This paper demonstrates the use of light-induced atomic desorption to load a lithium magneto-optical trap, analyzing desorption rates, wavelength thresholds, and background gas effects, suggesting a compact Li vapor source for sensors.

Contribution

The study provides the first detailed analysis of lithium desorption via light-induced atomic desorption, including wavelength dependence and background gas effects, for MOT loading.

Findings

Li MOT can be loaded with up to 4×10^4 atoms.

Desorption threshold wavelength is approximately 470 nm.

Background gas pressure increases by less than 50% during desorption.

Abstract

We demonstrate loading of a Li magneto-optical trap using light-induced atomic desorption. The magneto-optical trap confines up to approximately $4\times10^{4}$ $^{7}\text{Li}$ atoms with loading rates up to approximately $4\times10^{3}$ atoms per second. We study the Li desorption rate as a function of the desorption wavelength and power. The extracted wavelength threshold for desorption of Li from fused silica is approximately $470$ nm. In addition to desorption of lithium, we observe light-induced desorption of background gas molecules. The vacuum pressure increase due to the desorbed background molecules is $\lesssim50$ % and the vacuum pressure decreases back to its base value with characteristic timescales on the order of seconds when we extinguish the desorption light. By examining both the loading and decay curves of the magneto-optical trap, we are able to disentangle the trap decay rates due to background gases and desorbed lithium. Our results show that light-induced atomic desorption can be a viable Li vapor source for compact devices and sensors.