A passively pumped vacuum package sustaining cold atoms for more than 200 days

TL;DR

This paper demonstrates a passively pumped vacuum package that sustains cold atoms for over 200 days without ion pumps, advancing miniaturized atomic sensors.

Contribution

First successful demonstration of a long-term, passively pumped vacuum chamber for cold atoms, eliminating the need for active ion pumps in compact sensors.

Findings

Maintains MOT for over 200 days

Pressure kept below 2×10⁻⁷ Torr

Operates without ion pumps

Abstract

Compact cold-atom sensors depend on vacuum technology. One of the major limitations to miniaturizing these sensors are the active pumps -- typically ion pumps -- required to sustain the low pressure needed for laser cooling. Although passively pumped chambers have been proposed as a solution to this problem, technical challenges have prevented successful operation at the levels needed for cold-atom experiments. We present the first demonstration of a vacuum package successfully independent of ion pumps for more than a week; our vacuum package is capable of sustaining a cloud of cold atoms in a magneto-optical trap (MOT) for greater than 200 days using only non-evaporable getters and a rubidium dispenser. Measurements of the MOT lifetime indicate the package maintains a pressure of better than $2\times10^{-7}$ Torr. This result will significantly impact the development of compact atomic sensors, including those sensitive to magnetic fields, where the absence of an ion pump will be advantageous.