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arXiv:2606.19219

Spontaneous parametric down-conversion pumped by spatiotemporal structured light

Lukas Montenegro, Rafael F. Barros

quant-phphysics.opticsSubmitted Jun 17, 2026• Announced Jun 18, 2026• 0 citations
v1 · Jun 17, 2026v2 · Jun 19, 2026
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Abstract

Here we investigate the all-optical control of spectral correlations in spontaneous parametric down-conversion. We show that when photon pairs are projected onto high-order spatial modes, the spatial structure of the pump field defines the phase-matching function of the nonlinear interaction. Thus, by structuring the pump field in both space and spectrum, the biphoton spectral correlations are fully controlled.Considering a standard periodically-poled crystal as the nonlinear medium, we show that the Gouy phase matching method proposed here can generate both spectrally uncorrelated and high-dimensional spectrally entangled photon pairs, similarly to what is achieved with aperiodically-poled crystals. Furthermore, we show that our method can generate a wider class of quantum states if the pump field is a spatiotemporal wavepacket, that is, if its spatial and spectral structures are correlated.

Comments
7 pages, 6 figures

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