Coherence and mode decomposition of weak twin beams

TL;DR

This paper analyzes the properties of weak spatio-spectral twin beams using mode decomposition, exploring how pump parameters influence mode numbers and coherence, with implications for quantum optics applications.

Contribution

It introduces a detailed mode decomposition framework for weak twin beams, linking mode numbers to coherence properties in spatial and spectral domains.

Findings

Mode numbers depend on pump-beam parameters.

Spatial and spectral coherence are characterized by correlation functions.

Relations between mode numbers and coherence are established.

Abstract

Properties of weak spatio-spectral twin beams in paraxial approximation are analyzed using the decomposition into appropriate paired modes. Numbers of paired modes as well as numbers of modes in the signal (or idler) field in the transverse wave-vector and spectral domains are analyzed as functions of pump-beam parameters. Spatial and spectral coherence of weak twin beams is described by auto- and cross-correlation functions. Relation between the numbers of modes and coherence is discussed.