# Spatially-entangled Photon-pairs Generation Using Partial Spatially Coherent Pump Beam

## TL;DR

This paper experimentally demonstrates how varying the spatial coherence of a pump beam influences the spatial entanglement of photon pairs generated via SPDC, enabling tailored entanglement for quantum applications.

## Contribution

It introduces a method to control the degree of spatial entanglement in photon pairs by adjusting the pump's spatial coherence, supported by experimental validation.

## Key findings

- Spatial coherence affects photon pair entanglement
- Tailoring pump coherence controls entanglement degree
- Experimental results match theoretical predictions

## Abstract

We demonstrate experimental generation of spatially-entangled photon-pairs by spontaneous parametric down conversion (SPDC) using a partial spatially coherent pump beam. By varying the spatial coherence of the pump, we show its influence on the downconverted photon's spatial correlations and on their degree of entanglement, in excellent agreement with theory. We then exploit this property to produce pairs of photons with a specific degree of entanglement by tailoring of the pump coherence length. This work thus unravels the fundamental transfer of coherence occuring in SPDC processes, and provides a simple experimental scheme to generate photon-pairs with a well-defined degree of spatial entanglement, which may be useful for quantum communication and information processing