Highly efficient source for frequency-entangled photon pairs generated in a 3rd order periodically poled MgO-doped stoichiometric LiTaO3 crystal

TL;DR

This paper reports a highly efficient source of frequency-entangled photon pairs generated via spontaneous parametric down-conversion in a specially engineered MgO-doped LiTaO3 crystal, demonstrating high discreteness and confirmed entanglement.

Contribution

The work introduces a novel, highly efficient photon pair source using third-order quasi-phase matching in MgO-doped LiTaO3, with broad spectral range and robust entanglement verification.

Findings

High efficiency in photon pair generation

Broad spectral range with temperature variations

Confirmed frequency entanglement via quantum interference

Abstract

We present a highly efficient source for discrete frequency-entangled photon pairs based on spontaneous parametric down-conversion using 3rd order type-0 quasi-phase matching in a periodically poled MgO-doped stoichiometric LiTaO3 crystal pumped by a 355.66 nm laser. Correlated two-photon states were generated with automatic conservation of energy and momentum in two given spatial modes. These states have a wide spectral range, even under small variations in crystal temperature, which consequently results in higher discreteness. Frequency entanglement was confirmed by measuring two-photon quantum interference fringes without any spectral filtering.