Thin-film lithium niobate quantum photonics: review and perspectives

Photonics has proven to be a very attractive platform for quantum technologies, offering key features such as high-fidelity qubits and room-temperature signal processing. Advancements in integrated photonics are expected to further enhance these capabilities as the technology evolves from few-photon architectures to systems capable of generating and processing tens, possibly hundreds, of photons, marking critical progress toward scalable quantum information processing. Although each integrated platform has its own unique advantages and limitations, thin-film lithium niobate (TFLN) photonics has recently emerged as a strong contender thanks to its low-loss characteristics, large electro-optic and nonlinear coefficients, broad transparency window, and ultra-fast modulation capabilities. In this review, we examine the latest developments in TFLN quantum photonics and identify promising directions and challenges for future research in this field.