Dynamic rephasing in a telecom warm vapor quantum memory

TL;DR

This paper presents a dynamic rephasing protocol for warm vapor quantum memories that significantly extends coherence time and enables high-dimensional temporal mode processing at room temperature.

Contribution

The authors introduce and experimentally demonstrate a rephasing technique that counteracts Doppler dephasing, enhancing storage time and multiplexing capabilities in warm vapor quantum memories.

Findings

Extended storage time by a factor of 50

Achieved on-demand retrieval of four time-bin modes

Maintained high bandwidth and low noise

Abstract

The Off-Resonant Cascaded Absorption (ORCA) protocol in warm atomic vapors offers a scalable platform for high-bandwidth, low noise quantum memories, but its coherence time is fundamentally limited by Doppler-induced dephasing. We introduce and experimentally demonstrate a dynamic rephasing protocol that counteracts Doppler dephasing in a telecom-band ORCA quantum memory. By transferring the stored excitation to an auxiliary shelving state, we effectively reverse the accumulated Doppler phase and extend the storage time by a factor of 50 while preserving the memory's GHz bandwidth and low noise. Using this protocol, we then demonstrate on-demand storage and retrieval of four independent time-bin modes within a single warm vapor memory -- showing that Doppler dephasing can alternatively be harnessed for high-dimensional temporal mode processing. Our results establish rephasing in warm atomic vapors as a viable route toward high-bandwidth, temporally multiplexed quantum memories operating at room temperature.