Time ordering effects in the generation of entangled photons using nonlinear optical processes

TL;DR

This paper investigates how time ordering influences the joint spectral amplitude in photon generation processes like SPDC and SFWM, highlighting conditions where these effects are significant and identifying ideal sources for observing such modifications.

Contribution

It provides an intuitive framework to predict when time ordering effects alter the joint spectral amplitude in nonlinear photon generation processes.

Findings

Time ordering effects are significant when photons stay with the pump in the nonlinear medium.

Spectrally separable photon sources are ideal for observing time ordering modifications.

The study offers a predictive picture for when time ordering impacts photon spectral properties.

Abstract

We study the effects of time ordering in photon generation processes such as spontaneous parametric down-conversion (SPDC) and four wave mixing (SFWM). The results presented here are used to construct an intuitive picture that allows us to predict when time ordering effects significantly modify the joint spectral amplitude (JSA) of the photons generated in SPDC and SFWM. These effects become important only when the photons being generated lie with the pump beam that travels through the non-linear material for a significant amount of time. Thus sources of spectrally separable photons are ideal candidates for the observation of modifications of the JSA due to time ordering.