Intensity correlations in the forward four-wave mixing driven by a single pump

TL;DR

This paper investigates intensity fluctuations and correlations in four-wave mixing signals generated in cold rubidium, revealing how polarization and phase-noise conversion influence the observed correlations and Rabi oscillations.

Contribution

It provides a combined experimental and theoretical analysis of intensity correlations in four-wave mixing driven by a single pump laser, highlighting phase-noise effects and polarization configurations.

Findings

Cross-correlation observed in all configurations despite spectral differences

Resonant phase-noise to amplitude-noise conversion explains Rabi oscillations

Experimental setup uses a single CW laser with various polarization schemes

Abstract

We study the field intensity fluctuations of two independent four-wave mixing signals generated in a cold rubidium sample as well as the transmission signals. We employ an experimental setup using a single CW laser to induce the nonlinear process in a forward geometry using either parallel and circular or orthogonal and linear polarizations of the input fields. Even though the spectra of each experimental configuration are significantly different due to the distinct level structures of each scenario, both cases present intensit-intensity cross-correlation of the four-wave mixing signals. We also calculate the cross-correlation between the input fields and draft a theoretical model that points that resonant phase-noise to amplitude-noise conversion allows the observation of Rabi oscillations in the cross-correlation curves.