Noise Free On-Demand Atomic Frequency Comb Quantum Memory

TL;DR

This paper introduces a noise-free, on-demand quantum memory protocol using the Stark effect in atomic frequency combs, demonstrating high efficiency and signal-to-noise ratio in a solid-state system, with potential for longer storage times.

Contribution

The work extends the atomic frequency comb protocol with Stark effect control, achieving noise-free, on-demand quantum memory in solid-state systems with high efficiency and signal quality.

Findings

Achieved 38% recall efficiency for 0.8 μs storage in Pr$^{3+}$:Y$_2$SiO$_5$.

Realized high signal-to-noise ratio of 570 with weak-coherent states.

Projected storage times up to 100 μs without spin-wave storage.

Abstract

We present an extension of the atomic frequency comb protocol that utilizes the Stark effect to perform noise-free, on-demand, control. An experimental realization of this protocol was implemented in the Pr$^{3+}$:Y$_2$SiO$_5$ solid-state system, and a recall efficiency of 38\% for a 0.8 $\mu$s storage time was achieved. Experiments were performed with both bright pulses as well as weak-coherent states, the latter achieving a signal-to-noise ratio of $570 \pm 120$ using input pulses with an average photon number of $\sim 0.1$. The principal limitation for a longer storage time was found to be the minimum peak width attainable for Pr$^{3+}$:Y$_2$SiO$_5$. We employ an adaptation of an established atomic-frequency comb model to investigate an on-demand, wide-bandwidth, memory based on Eu$^{3+}$:Y$_2$SiO$_5$. From this we determine that a storage time as long as 100 $\mu$s may be practical even without recourse to spin-wave storage.