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arXiv · 2512.24053

Entangled photon triplets using lithium niobate nanophotonics

Nathan A. Harper·Ayantika Sengupta·Emily Y. Hwang·Scott K. Cushing
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Abstract

Multiphoton states are needed for quantum communication and computation. Multiphoton states are significantly more difficult to generate than one- and two-photon states because two individual down-conversion processes must be cascaded. Only efficiencies of $<100$ Hz/mW have been reported to date. We integrate two down-converters on the same thin-film lithium niobate waveguide, significantly enhancing the cascaded process efficiency to $237 \pm 36$ kHz/mW. The measured $4.4 \times 10^{-5}$ probability of the second down-converter, which sets the limit on detectable triplet rates, exceeds those of previous triplet sources by an order of magnitude and demonstrates a path towards MHz rates of triplets for quantum applications.

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Nathan A. Harper, Ayantika Sengupta, Emily Y. Hwang, Scott K. Cushing. 2025-12-30. Entangled photon triplets using lithium niobate nanophotonics. https://arxiv.org/abs/2512.24053

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