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arXiv · 2305.08345

Exciton-Enhanced Spontaneous Parametric Down-Conversion in Two-Dimensional Crystals

Fengyuan Xuan·MingRui Lai·Yaze Wu·Su Ying Quek
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Abstract

We show that excitonic resonances and interexciton transitions can enhance the probability of spontaneous parametric down-conversion, a second-order optical response which generates entangled photon pairs. We benchmark our ab initio many-body calculations using experimental polar plots of second harmonic generation in NbOI$_2$, clearly demonstrating the relevance of excitons in the nonlinear response. A strong double-exciton resonance in 2D NbOCl$_2$ leads to giant enhancement in the second order susceptibility. Our work paves the way for the realization of efficient ultrathin quantum light sources.

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Fengyuan Xuan, MingRui Lai, Yaze Wu, Su Ying Quek. 2023-05-15. Exciton-Enhanced Spontaneous Parametric Down-Conversion in Two-Dimensional Crystals. https://doi.org/10.1103/physrevlett.132.246902

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