Spectrally uncorrelated biphotons generated from `the family of BBO crystal'

TL;DR

This paper theoretically explores the generation of spectrally uncorrelated biphoton states from 14 crystals in the BBO family, achieving high purity and indistinguishability for quantum photonics applications across a wide wavelength range.

Contribution

It identifies new BBO family crystals suitable for generating high-purity, spectrally uncorrelated biphotons with broad wavelength coverage and high nonlinear efficiency.

Findings

Heralded single-photon purity up to 0.98 without filtering

Hong-Ou-Mandel interference visibility of 98% without filtering

Group-velocity matching in 14 different BBO family crystals across various wavelengths

Abstract

Spectrally intrinsically uncorrelated biphoton states generated from nonlinear crystals are very important but rare resources for quantum photonics and quantum information applications. Previously, such biphoton states were generated from several kinds of crystals, however, their wavelength ranges and nonlinear efficiencies were still limited for various applications. In order to explore new crystal for wider wavelength range and higher nonlinear efficiency, here we theoretically study the generation of spectrally uncorrelated biphoton states from 14 crystals in the `BBO family', including BBO, CLBO, KABO, KBBF, RBBF, CBBF, BABF, BiBO, LBO, CBO, LRB4, LCB, YCOB, and GdCOB. They satisfy three kinds of group-velocity matching condition from near-infrared to telecom wavelengths. Furthermore, heralded single photons can be generated with a purity as high as 0.98, which is achieved without any narrow filtering. The indistinguishability of photons from independent sources is examined by the Hong-Ou-Mandel interference, which results in a visibility of 98% also without any further filtering, i.e., photons from different heralded single-photon sources are highly indistinguishable. Our study may provide single-photon sources with good performance for quantum information processing at near-infrared and telecom wavelengths.