窄带超纠缠光源的实验研究

The photons in narrow-band hyperentanglement photon sources can be entangled in several freedoms at the same time, which expands the number of quantum bits dramatically. Meanwhile, the frequency bandwidth of this sources (dozens of MHz- hundreds of MHz) can match solid state systems, then the quantum storage of photons based on solid state systems can be realized. This kind of sources has very important future prospects in the scalable linear optical quantum computation and quantum networks. This project will research the output of the higher order Laguerre-Gaussian optical beams from the resonant cavity. Making use of the orbit angular momentum (OAM) entangled states with polarization produced from the cavity-enchanced spontaneous parametric down-conversion, we will try to develop a type of narrow-band polarization-OAM hyperentanglement photon sources using linear optical method. We will research quantum decoherece, quantum correlation and quantum nonlocality of this sources. On the other hand, we will analyze the coupling mechanism between photons and whispering gallery mode optical microresonators and will research the storage mechanism of single photon based on solid state microresonators, which lays the foundation for the next generation of scalable optical quantum information processing.

窄带超纠缠光源可以同时实现光子在多个自由度上的纠缠，这极大地扩展了量子比特的数目，同时光源的线宽（几十兆赫至几百兆赫）可以匹配固态系统，实现光子基于固态系统的量子存储，在可扩展的线性光学量子计算和量子网络中有重要的应用前景。本项目将研究谐振腔内Laguerre-Gaussian光高阶模式的共振输出，利用腔增强自发参量下转换方法产生携带极化的轨道角动量纠缠态。在此基础上，通过线性光学手段，我们将尝试制备窄带极化-轨道角动量超纠缠光源，研究光源的退相干机制，以及其量子关联、量子非定域特性。此外，我们将分析光子与回音壁模式光学微腔的耦合机制，研究单光子基于微腔的量子存储机制，为构筑下一代可扩展的光学量子信息处理技术打下科学基础。

本课题主要研究是利用非线性晶体和光学技术手段制备腔内产生的轨道角动量纠缠光源和预兆单光子源，研究光源的非经典特性和量子测量。实验上，腔内产生的轨道角动量光子态的设计方案已经实现，基于非线性晶体的预兆单光子源和偏振纠缠光源也已经实验实现。. 此外，实验上在相同的测量装置和不同的测量事件定义下，测量了经典光场（相干态）和量子光场（单光子态），检验了非互文的KCBS不等式，实验证实了单光子态的互文性。发现随着测量事件的不同定义，经典光场也具备互文性，并且给出了互文性从经典到量子转变的一个边界。我们的结果强调了测量事件的不同定义对实验检验互文性至关重要。 . 我们设计了一种手性单光子和微环腔相互作用的微芯系统，显示出该系统可以实现高达几个GHz带宽的单光子量级的光隔离，并且能够实现量子点到微腔的单向发射，这为基于芯片的量子信息处理和量子网络中实现多功能的手性单光子互连打开了一条通道。