双光子自旋-轨道超纠缠态与高维量子信息处理的实验研究

光子是量子信息的理想载体。自旋和轨道角动量属于光子的两个独立自由度，都可用以信息编码。但是，国际上利用光子自旋与轨道这两个自由度同时编码高维量子信息的实验研究目前还比较缺乏。因此，本项目将致力于研究双光子的自旋-轨道超纠缠态及其在构建高维Hilbert空间中的应用潜力。具体地，我们将在实验上搭建一套完善的双光子超纠缠系统，用于研究自旋-轨道超纠缠态的制备与调控，特别是从基础物理和应用物理两个层面来研究它的应用价值：（1）基础物理方面，基于高维的自旋-轨道复合Hilbert空间，实验研究双光子的超纠缠态分析，以及Hardy非定域性原理的递推式论证，从而为量子力学一些基本概念的检验提供一个新的视角；（2）应用物理方面，将光子自旋-轨道态调控和量子关联成像有效结合，着重研究如何利用超纠缠态提高量子成像的对比度和保真度，这有望用于未来量子网络中实现量子图像的高品质传输。

Single photon is an ideal candidate for quantum information. Spin and orbital angular momentum (OAM) are two dependent photonic degrees of freedom, each of which can be exploited for the information coding. But, we find that there are quite few researches reporting the simultaneous employment of both spin and OAM for the high-dimensional quantum information applications. Here we focus on the spin-orbit hyper-entangled state and exploit its potential in constructing a very high-dimensional Hilbert space. Particularly, we will built up an experimental system for the generation and manipulation of two-photon spin-orbit hyper-entanglement, and demonstrate their appications from both the fundamental and applied points of view. The aim of our project mainly includes: (1) We will study the hyper-entanglement state analysis, and perform the ladder proof of Hardy's nonlocality theory in the high-dimensional spin-orbit Hilbert space, which will provide a new perspective for understanding the fundamental concepts of quantum mechanics. (2) We will combine effectively the spin-orbit hyper-entanglement with quantum imaging, and show the new way to improve the edge contrast and fidelity of the image, which holds promise for quantum image transmission with high quality in the future quantum networks.