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

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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Cited by in corpus (7)

• Exciton enhanced nonlinear optical responses in monolayer h-BN and MoS2: Insight from first-principles exciton-state coupling formalism and calculations
• Spin-chirality-driven second-harmonic generation in two-dimensional magnet CrSBr
• Colossal terahertz emission with ultrafast tunability based on van der Waals ferroelectric NbOI${}_2$
• Enhancement of nonclassical properties of two-mode squeezed vacuum state with postselected von Neumann measurement
• Efficient high-quality photon pair generation in modal phase-matched thin-film lithium niobate micro-ring resonators
• Observation of an isolated flat band in the van der Waals crystal NbOCl${}_2$
• Perturbative second-order optical susceptibility of bulk materials: a symmetry-enforced return to non-orthogonal localized basis sets