Cavity-enhanced and spatial-multimode spin-wave-photon quantum interface

TL;DR

This paper demonstrates a cavity-enhanced, spatially multiplexed quantum interface using cold atoms, achieving high retrieval efficiency and long storage times for multiple modes, advancing quantum memory technology.

Contribution

The work introduces a cavity design supporting multiple modes with uniform optical length, enabling efficient, multimode quantum memory with extended storage times.

Findings

Achieved 70% intrinsic retrieval efficiency at zero delay.

Demonstrated 0.6 ms storage time with high cross-correlation.

Supported 6 spatial modes with uniform optical properties.

Abstract

Practical realizations of quantum repeaters require quantum memory simultaneously providing high retrieval efficiency, long lifetime and multimode storages. So far, the combination of high retrieval efficiency and spatially multiplexed storages into a single memory remains challenging. Here, we set up a ring cavity that supports an array including 6 TEM00 modes and then demonstrated cavity enhanced and spatially multiplexed spin wave photon quantum interface (QI). The cavity arrangement is according to Fermat' optical theorem, which enables the six modes to experience the same optical length per round trip. Each mode includesn horizontal and vertical polarizations. Via DLCZ process in a cold atomic ensemble, we create non classically correlated pairs of spin waves and Stokes photons in the 12 modes. The retrieved fields from the multiplexed SWs are enhanced by the cavity and the average intrinsic retrieval efficiency reaches 70% at zero delay. The storage time for the case that cross-correlation function of the multiplexed QI is beyond 2 reaches 0.6ms .