Three-photon states in nonlinear crystal superlattices

TL;DR

This paper proposes a method to generate controllable three-photon states using cascaded parametric down-conversion in nonlinear superlattice structures, enabling entangled and heralded multiphoton quantum states with tailored spectral properties.

Contribution

It introduces a novel scheme utilizing superlattice structures for efficient three-photon state generation and entanglement, including dispersion compensation techniques and analysis of photon correlations.

Findings

Successful generation of polarization-entangled GHZ states.

Demonstration of dispersion compensation in superlattice structures.

Analysis of photon-number distributions and correlations in intracavity splitting.

Abstract

It has been a longstanding goal in quantum optics to realize controllable sources generating joint multiphoton states, particularly, photon triplet with arbitrary spectral characteristics. We demonstrate that such sources can be realized via cascaded parametric down-conversion (PDC) in superlattice structures of nonlinear and linear segments. We consider scheme that involves two parametric processes: $\omega_{0}\rightarrow\omega_{1}+\omega_{2}$, $\omega_{2}\rightarrow\omega_{1}+\omega_{1}$ under pulsed pump and investigate spontaneous creation of photon triplet as well as generation of high-intensity mode in intracavity three-photon splitting. We show preparation of Greenberger-Horne-Zeilinger polarization entangled states in cascaded type-II and type-I PDC in framework of consideration dual-grid structure that involves two periodically-poled crystals. We demonstrate the method of compensation of the dispersive effects in non-linear segments by appropriately chosen linear dispersive segments of superlattice for preparation heralded joint states of two polarized photons. In the case of intracavity three-photon splitting, we concentrate on investigation of photon-number distributions, third-order photon-number correlation function as well as the Wigner functions. These quantities are observed both for short interaction time intervals and in over transient regime, when dissipative effects are essential.