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Updated: Jun 28, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Directionally tunable co- and counterpropagating photon pairs from a nonlinear metasurface
Maximilian A Weissflog1,2, Jinyong Ma3, Jihua Zhang3,4
1Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, 07745 Jena, Germany.
Abstract:
Nonlinear metasurfaces have recently been established as a new platform for generating photon pairs via spontaneous parametric down-conversion. While for classical harmonic generation in metasurfaces a high level of control over all degrees of freedom of light has been reached, this capability is yet to be developed for photon-pair generation. In this work, we theoretically and experimentally demonstrate for the first time precise control of the emission angle of photon pairs generated from a nonlinear metasurface. Our measurements show angularly tunable pair generation with high coincidence-to-accidental ratio for both co- and counterpropagating emission. The underlying principle is the transverse phase matching of guided-mode resonances with strong angular dispersion in a nonlinear metasurface consisting of a silicon dioxide grating on a nonlinear lithium niobate guiding layer. We provide a straightforward design strategy for photon-pair generation in such a device and find very good agreement between the calculations and experimental results. Here, we use all-optical emission angle tuning by means of the pump wavelength; however, the principle could be extended to modulation via the electro-optic effect in lithium niobate. In sum, this work provides an important addition to the toolset of subwavelength thickness photon-pair sources.
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