Quantum-preserving telecom conversion of atomic biphotons

TL;DR

This paper demonstrates efficient telecom frequency conversion of atomic biphotons using a diamond-type atomic ensemble, preserving their quantum properties and enabling practical quantum communication interfaces.

Contribution

It introduces a novel atomic ensemble-based frequency converter that maintains quantum coherence and correlations during telecom conversion.

Findings

Efficient conversion while preserving quantum antibunching.

Retention of strong quantum correlations in converted photons.

Agreement of experimental results with microscopic spectral models.

Abstract

We experimentally demonstrate telecom frequency conversion of atomic biphotons using a diamond-type atomic ensemble. By spectrally engineering heralded photons and optimizing the atomic converter, efficient conversion is achieved while preserving the temporal waveform and nonclassical antibunching behavior. The converted photons retain strong quantum correlations and well-defined wavepackets, demonstrating preservation of dynamical quantum properties beyond photon-statistics-based benchmarks. The measured performance agrees with a microscopic model that captures the spectral acceptance and parameter dependence of the converter. These results establish a practical interface between atomic photon sources and telecom fiber networks, enabling quantum interference and distributed quantum communication.