Manipulating the symmetry of transverse momentum entangled biphoton states

TL;DR

This paper introduces a method to manipulate and verify the symmetry of transverse momentum entangled biphoton states using a spatially variable phase object and a Hong-Ou-Mandel interferometer, enabling custom phase generation in entangled states.

Contribution

The paper presents a novel scheme for engineering the symmetry of momentum-entangled biphoton states and verifying it with a specialized interferometer setup.

Findings

Successful manipulation of momentum space symmetry in biphoton states

Demonstration of state generation with arbitrary exchange phase

Verification of symmetry via Hong-Ou-Mandel interference

Abstract

Bell states are a fundamental resource in photonic quantum information processing. These states have been generated successfully in many photonic degrees of freedom. Their manipulation, however, in the momentum space remains challenging. Here, we present a scheme for engineering the symmetry of two-photon states entangled in the transverse momentum degree of freedom through the use of a spatially variable phase object. We demonstrate how a Hong-Ou-Mandel interferometer must be constructed to verify the symmetry in momentum entanglement via photon "bunching"/"anti-bunching" observation. We also show how this approach allows generating states that acquire an arbitrary phase under the exchange operation.