Spectral Correlation Measurements at the Hong-Ou-Mandel Interference Dip

TL;DR

This paper introduces an efficient spectral correlation measurement tool for photons in Hong-Ou-Mandel interference, demonstrating its effectiveness in analyzing spectral effects on interference visibility and potential for improving multi-source quantum applications.

Contribution

The paper presents a novel spectral correlation measurement method specifically designed for Hong-Ou-Mandel interference setups, enhancing analysis of spectral effects on quantum interference.

Findings

Interference visibility decreases with increased photon frequency spread.

Unfiltered visibility achieved was 92.0%, improved to 97% with filtering.

The tool aids in studying spectral correlations affecting quantum interference quality.

Abstract

We present an efficient tool capable of measuring the spectral correlations between photons emerging from a Hong-Ou-Mandel interferometer. We show that for our spectrally factorizable spontaneous downconversion source the Hong-Ou-Mandel interference visibility decreases as the photons frequency spread is increased to a maximum of 165 nm. Unfiltered, we obtained a visibility of $92.0 \pm 0.2 \%$. The maximum visibility was $97 \pm 0.2 \%$ after applying filtering. We show that the tool can be useful for the study of spectral correlations that impair high-visibility and high-fidelity multi-source interference applications.