Spatial correlations in parametric down-conversion

TL;DR

This paper reviews the progress in understanding spatial correlations in photon pairs generated by parametric down-conversion, highlighting theoretical, experimental, and application advances over the past two decades.

Contribution

It provides a comprehensive overview of the key developments, techniques, and fundamental insights in the study of spatial correlations in parametric down-conversion.

Findings

Advances in quantum imaging techniques

Fundamental tests of quantum mechanics such as Bell inequalities

Development of applications in quantum information

Abstract

The transverse spatial effects observed in photon pairs produced by parametric down-conversion provide a robust and fertile testing ground for studies of quantum mechanics, non-classical states of light, correlated imaging and quantum information. Over the last 20 years there has been much progress in this area, ranging from technical advances and applications such as quantum imaging to investigations of fundamental aspects of quantum physics such as complementarity relations, Bell's inequality violation and entanglement. The field has grown immensely: a quick search shows that there are hundreds of papers published in this field. The objective of this article is to review the building blocks and major theoretical and experimental advances in the field, along with some possible technical applications and connections to other research areas.