2021/09/30 by Túlio Brito Brasil, Valeriy Novikov, Brasil, Tulio Brito +7 · 2 citations
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Mechanical and Optical Resonators #Optics (physics.optics) #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.2110.00066
openalex publication_date 2021/09/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Entanglement is the backbone of quantum information science and its applications. Entangled states of light are necessary for distributed quantum protocols, quantum sensing and quantum internet. A distributed quantum network requires entanglement between light modes of different colours optimized for interaction with the nodes as well as for communication between them. Here we demonstrate a high-purity Einstein-Podolsky-Rosen (EPR) entangled state between light modes with the wavelengths separated by more than 200 nm. The modes display -7.7±0.5 dB of two-mode entanglement and an overall state purity of 0.63±0.16. Entanglement is observed over five octaves of sideband frequencies from rf down to audio-band. In the context of two-colour entanglement, the demonstrated combination of high state purity, strong entanglement, and extended frequency range paves the way to new matter-light quantum protocols, such as teleportation between disparate quantum systems, quantum sensing and quantum-enhanced gravitational wave interferometry. The scheme demonstrated here can be readily applied towards entanglement between telecom wavelengths and atomic quantum memories.