Broad Spiral-Bandwidth of Orbital Angular Momentum Interface between Photon and Memory

The complex interactions between orbital angular momentum (OAM) light and atoms are particularly intriguing in the areas of quantum optics and quantum information science. Building a versatile high-dimensional quantum network needs broad spiral-bandwidth for preparing higher-quanta OAM mode and resolving the bandwidth mismatch in spatial space and etc. Here, we experimentally demonstrate a broad spiral-bandwidth quantum interface between photon and memory. Through twisted fields of the writing and reading, the correlated OAM distribution between photon and memory is significantly broadened. This broad spiral-bandwidth quantum interface could be spanned in multiplexing regime and could work in high-quanta scenario with capability of |l|=30, and we demonstrate the entanglement within 2-D subspace with a fidelity of 80.5\text{\textpm}4.8\% for high l. Such state-of-the-art technology to freely control the spatial distribution of OAM memory is very helpful to construct high-dimensional quantum networks and provides a benchmark in the field of actively developing methods to engineer OAM single photon from matters.
Comment: 8 pages, 6 figures