# High-speed noise-free optical quantum memory

## TL;DR

This paper introduces a noise-free quantum memory protocol using two-photon off-resonant cascaded absorption, enabling high-speed, noise-free storage of single photons in warm atomic vapour for quantum networks.

## Contribution

The paper presents the first demonstration of a noise-free, high-speed quantum memory platform based on ORCA, suitable for scalable quantum networks.

## Key findings

- Successful storage of GHz-bandwidth heralded single photons without added noise
- Photon statistics remain unaltered upon recall, confirming noise-free operation
- Platform is compatible with low-latency quantum network applications

## Abstract

Quantum networks promise to revolutionise computing, simulation, and communication. Light is the ideal information carrier for quantum networks, as its properties are not degraded by noise in ambient conditions, and it can support large bandwidths enabling fast operations and a large information capacity. Quantum memories, devices that store, manipulate, and release on demand quantum light, have been identified as critical components of photonic quantum networks, because they facilitate scalability. However, any noise introduced by the memory can render the device classical by destroying the quantum character of the light. Here we introduce an intrinsically noise-free memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We consequently demonstrate for the first time successful storage of GHz-bandwidth heralded single photons in a warm atomic vapour with no added noise; confirmed by the unaltered photon statistics upon recall. Our ORCA memory platform meets the stringent noise-requirements for quantum memories whilst offering technical simplicity and high-speed operation, and therefore is immediately applicable to low-latency quantum networks.