Spectral mapping of polarization-correlated photon-pair sources using quantum-classical correspondence

TL;DR

This paper presents a novel method for spectral characterization of polarization-correlated photon-pair sources using classical sum-frequency generation, simplifying the process and enabling faster, more practical quantum source monitoring.

Contribution

The study introduces a quantum-classical correspondence technique to reconstruct the joint spectral intensity of photon pairs via classical measurements, reducing complexity and cost.

Findings

Successfully reconstructed joint spectral intensity using classical SFG measurements

Demonstrated the technique on a Ti:PPLN waveguide SPDC source

Enabled faster, more practical spectral characterization of quantum sources

Abstract

Direct spectral characterization of a quantum photon-pair source usually involves cumbersome, costly, and time-consuming detection issues. In this study, we experimentally characterize the spectral properties of a type-II phase-matched spontaneous parametric down-conversion (SPDC) source based on a titanium-diffused periodically poled lithium niobate (Ti:PPLN) waveguide. The characterization of the spectral information of the generated cross-polarized photon pairs is of importance for the use of such sources in applications including quantum information and communication. We demonstrate that the joint spectral intensity of the cross-polarized photon-pair source can be fully reconstructed using the quantum-classical correspondence through classical sum-frequency generation (SFG) measurements. This technique, which uses a much less complex detection system for visible light, opens the possibility of fast monitoring and control of the quantum state of (polarization-correlated) photon-pair sources to facilitate the realization of a stable and high-usability quantum source.