Compact 2D Nonlinear Photonic Crystal Source of Beamlike Path Entangled Photons

TL;DR

This paper presents a compact 2D nonlinear photonic crystal that directly generates path-entangled photons with controlled spatial, spectral, and polarization properties, eliminating the need for beam-splitters.

Contribution

A novel, fabricated 2D nonlinear crystal source that directly produces path-entangled photons through two simultaneous PDC processes.

Findings

Direct generation of path-entangled photons demonstrated.

Interference of coherent path amplitudes observed.

Controlled spatial, spectral, and polarization properties achieved.

Abstract

We demonstrate a method to generate entangled photons with controlled spatial shape by parametric down conversion (PDC) in a 2D nonlinear crystal. A compact and novel crystal source was designed and fabricated, generating directly path entangled photons without the use of additional beam-splitters. This crystal supports two PDC processes, emitting biphotons into two beamlike modes simultaneously. Two coherent path entangled amplitudes of biphotons were created and their interference observed. Our method enables the generation of entangled photons with controlled spatial, spectral and polarization properties.