Photonics offers unique capabilities for quantum information processing (QIP) such as room-temperature operation, the scalability of nanophotonics, and access to ultrabroad bandwidths and consequently ultrafast operation. Ultrashort-pulse sources of quantum states in nanophotonics are an important building block for achieving scalable ultrafast QIP, however, their demonstrations so far have been sparse. Here, we demonstrate a femtosecond biphoton source in dispersion-engineered periodically poled lithium niobate nanophotonics. We measure 17 THz of bandwidth for the source centered at 2.09 \textmu m, corresponding to a few optical cycles, with a brightness of 8.8 GHz/mW. Our results open new paths towards realization of ultrafast nanophotonic QIP.
@article{arxiv.2402.05163,
title = {Ultra-Short Pulse Biphoton Source in Lithium Niobate Nanophotonics at 2$\text{\mu}$m},
author = {James Williams and Rajveer Nehra and Elina Sendonaris and Luis Ledezma and Robert M. Gray and Ryoto Sekine and Alireza Marandi},
journal= {arXiv preprint arXiv:2402.05163},
year = {2024}
}