A Frequency-Multiplexed Coherent Electro-Optic Memory in Rare Earth Doped Nanoparticles

TL;DR

This paper demonstrates a broadband, frequency-multiplexed quantum memory in rare earth doped nanoparticles, achieving coherent light storage with high phase fidelity using the SEMM protocol.

Contribution

It introduces a novel frequency-multiplexed coherent optical memory in rare earth doped nanoparticles with broadband operation and high phase fidelity.

Findings

Achieved up to 40 μs light storage time.

Demonstrated frequency-multiplexing capability.

Measured a Stark coefficient of 50 kHz/(V/cm) across 15 GHz.

Abstract

Quantum memories for light are essential components in quantum technologies like long-distance quantum communication and distributed quantum computing. Recent studies have shown that long optical and spin coherence lifetimes can be observed in rare earth doped nanoparticles, opening exciting possibilities over bulk materials e.g. for enhancing coupling to light and other quantum systems, and material design. Here, we report on coherent light storage in Eu$^{3+}$:Y$_2$O$_3$ nanoparticles using the Stark Echo Modulation Memory (SEMM) quantum protocol. We first measure a nearly constant Stark coefficient of 50 kHz/(V/cm) across a bandwidth of 15 GHz, which is promising for broadband operation. Storage of light using SEMM is then demonstrated for times up to 40 $\mu$s. Pulses with two different frequencies are also stored, confirming frequency-multiplexing capability, and are used to demonstrate the memory high phase fidelity.