Continuous Accumulation of Cold Atoms in an Optical Cavity

TL;DR

This paper demonstrates a method for continuously accumulating and cooling atoms inside an optical cavity, enabling steady-state quantum interfaces crucial for quantum sensing and processing.

Contribution

It introduces a light-shift manipulation technique that allows efficient, continuous atom accumulation in a cavity, advancing steady-state quantum system development.

Findings

Achieved continuous accumulation of sub-Doppler-cooled rubidium atoms in a cavity.

Maintained a steady-state ensemble of millions of atoms below 10 μK.

Established a pathway for continuous cavity-QED systems and long-duration quantum sensors.

Abstract

Continuously operating atom-light interfaces represent a key prerequisite for steady-state quantum sensors and efficient quantum processors. Here, we demonstrate continuous accumulation of sub-Doppler-cooled atoms in a shallow intracavity dipole trap, realizing this regime. The key ingredient is a light-shift manipulation that creates spatially varying cooling parameters, enabling efficient capture and accumulation of atoms within a cavity mode. Demonstrated with rubidium atoms, a continuous flux from a source cell is funneled through the magneto-optical trap into the cavity mode, where the atoms are cooled and maintained below $10~\mu\text{K}$ in steady state without time-sequenced operation. We characterize the resulting continuously maintained ensemble of millions of atoms and its collective coupling to the cavity field, establishing a route toward continuously operated cavity-QED systems and long-duration atomic and hybrid quantum sensors.