2025/10/04 by Peng, Xu-Jie, Kong, Ling-Xuan, Lu, He · 1 citation
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2510.03620
The polarization-entangled photon source (PEPS) at non-degenerated wavelengths is pivotal to connect quantum systems working at different wavelengths, with the assistance of quantum teleportation. Here, a compact Sagnac-type photon source is designed and demonstrated, in which two photons with wavelengths at 810 and 1550~nm are highly entangled in polarization degree of freedom. The two photons are generated from a periodically poled lithium niobate crystal pumped with a 532~nm continuous-wave laser, via type-0 nondegenerate spontaneous parametric down-conversion. The polarization of three lights is rotated by a single periscope, which makes the Sagnac interferometer compact and stable. The generated two photons are with high brightness of 3×104 pairs/s/mW, which are highly entangled with fidelity of 0.985±0.002. The entanglement is verified by violating the Clauser-Horne-Shimony-Holt inequality with \mathcal S =2.756±0.007. Finally, teleportation is demonstrated with this nondegenerate source, in which photonic states at 810~nm is teleported to 1550~nm with fidelity of 0.955±0.003.