Quantum interferometric generation of polarization entangled photons

TL;DR

This paper demonstrates a novel quantum interferometric scheme that efficiently generates high-quality polarization entangled photons without postselection, advancing quantum information technology applications.

Contribution

The authors introduce a quantum interferometric setup using a double-pass Sagnac interferometer to produce polarization entangled photons with high efficiency and broadband distribution, eliminating the need for postselection.

Findings

High emission rate of entangled photons achieved

Degenerate photon pairs separated without postselection

Effective use of quantum interference for quantum information

Abstract

Quantum interference, like Hong-Ou-Mandel interference, has played an important role to test fundamental concepts in quantum physics. We experimentally show that the multiple quantum interference effects enable the generation of high-performance polarization entangled photons. These photons have a high-emission rate, are degenerate, have a broadband distribution, and are postselection free. A quantum interferometric scheme, based on a round-trip configuration of a double-pass polarization Sagnac interferometer, makes it possible to use the large generation efficiency of polarization entangled photons in the process of parametric down-conversion and to separate degenerate photon pairs into different optical modes with no requirement of postselection. We demonstrate experimentally that multiple quantum interference is not only an interesting fundamental quantum optical phenomenon but can be used for novel photonic quantum information technologies.