Photon pair source without spectral correlation

Abstract

The invention discloses a photon pair source without spectral correlation. The photon pair source comprises a laser light source and a periodically poled potassium titanyl phosphate crystal, the periodically poled potassium titanyl phosphate crystal is a nonlinear crystal with II-type phase matching, and the periodically poled potassium titanyl phosphate crystal is used for generating photon pairswithout spectral correlation according to the parametric down-conversion process of laser emitted by the laser light source, wherein the polarization region of the II-type phase-matched periodicallypolarized potassium titanyl phosphate crystal is divided into a central region and two edge regions in the laser incident direction. By reasonably designing the duty ratio of the central region and the crystal length, the photon yield of the photon pair source is in Gaussian distribution, the problem of time distinguishability and the problem of spectrum distinguishability are solved, and the original brightness of photons is guaranteed while the photons are irrelevant to the spectrum. The photon pair source is convenient to adjust in practical application, high in integration level and easy to expand.

Description

technical field [0001] The present disclosure relates to the technical field of quantum information processing, in particular to a source of photon pairs without spectral correlation based on periodically poled potassium titanyl phosphate crystals. Background technique [0002] Entangled state is the core resource in the field of quantum information, it is Called "the essence of quantum mechanics", it exhibits the peculiar properties of quantum theory such as coherence, probability and spatial non-locality, and has been widely used in quantum cryptography, quantum state teleportation, quantum In the booming field of quantum information such as entanglement exchange, quantum storage and quantum computing. [0003] In the field of traditional linear optical quantum information, there are many ways to generate entangled photon pairs. At present, the most commonly used method is to use nonlinear optical crystals such as β-barium metaborate crystal (BBO) or periodically poled p...

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Problems solved by technology

[0005] In view of the above technical problems, this disclosure proposes a spectrally unrelated photon pair source based on periodically poled potassium titanyl phosphate crystals, which is used to solve at least the existing general standard periodic poled crystal (PPKTP) photon pair source. The yield distribution will be limited by the side lobes of the standard phase matching function, and the spectral distinction between the generated photons must use narrow-band filters to improve the photon purity and entanglement fidelity but reduce the output brightness of the photon source itself. , and problems with more complicated practical operations

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