Transfer of angular spectrum in parametric down-conversion with structured light

TL;DR

This paper presents a formal method to transfer the angular spectrum in parametric down-conversion using structured light, enabling the creation of entangled photon states with polarization-dependent correlations for quantum communication.

Contribution

It introduces a novel formal approach for angular spectrum transfer in PDC with structured pump beams, facilitating tailored entangled states for quantum applications.

Findings

Demonstrates polarization-dependent transverse correlations in entangled photon pairs.

Shows the transfer of vector beam profiles to entangled photons.

Provides a framework for designing pump beams and measurement strategies.

Abstract

We develop the formal approach to the angular spectrum transfer in parametric down-conversion that allows pumping with a structured beam. The scheme is based on an entangled photon source pumped by a laser beam structured with a vector-vortex polarization profile. This creates a two-photon quantum state exhibiting polarization-dependent transverse correlations that can be accessed through coincidence measurements on the spatially separated photons. The calculated correlations are shown to present a spin-orbit profile typical of vector beams, however, distributed on separate measurement regions. Our approach allows the design of the pump beam vector spatial structure and measurement strategies for potential applications of these entangled states, such as in quantum communication.