Telecom-heralded single photon absorption by a single atom

TL;DR

This paper demonstrates a quantum interface that efficiently converts and transmits photons between near-infrared and telecom wavelengths, enabling high-rate single-photon absorption by a single atom, advancing quantum communication technologies.

Contribution

It introduces a novel photonic interface using a resonant optical parametric oscillator for high-rate, narrowband photon pair generation tuned to atomic and telecom wavelengths.

Findings

Achieved over 2.5 million photon pairs per second.

Demonstrated single-photon absorption by a trapped ion at 670 Hz.

Successfully linked atomic transitions with telecom wavelengths.

Abstract

We present, characterize, and apply a photonic quantum interface between the near infrared and telecom spectral regions. A singly resonant optical parametric oscillator (OPO) operated below threshold, in combination with external filters, generates high-rate ($>2.5\cdot10^6~{\rm s}^{-1}$) narrowband photon pairs ($\sim 7$ MHz bandwidth); the signal photons are tuned to resonance with an atomic transition in Ca$^+$, while the idler photons are at telecom wavelength. Quantum interface operation is demonstrated through high-rate absorption of single photons by a single trapped ion ($\sim 670~{\rm s}^{-1}$), heralded by coincident telecom photons.