Detection of the ultranarrow temporal correlation of twin beams via sum-frequency generation

TL;DR

This paper demonstrates ultranarrow 6 femtosecond temporal correlation of twin beams generated by parametric down-conversion using sum-frequency generation, highlighting the importance of achromatic imaging and spatial control.

Contribution

It introduces a method to measure ultranarrow temporal correlations in twin beams via sum-frequency generation, emphasizing achromatic imaging and spatial degrees of freedom control.

Findings

Achieves 6 fs temporal correlation measurement.

Shows effects of spatial filtering and imaging imperfections.

Provides a theoretical model matching experimental results.

Abstract

We demonstrate the ultranarrow temporal correlation (6 fs full width half maximum) of twin beams generated by parametric down-conversion, by using the inverse process of sum-frequency generation. The result relies on an achromatic imaging of a huge bandwith of twin beams and on a careful control of their spatial degrees of freedom. The detrimental effects of spatial filtering and of imperfect imaging are shown toghether with the theoretical model used to describe the results.