基于原子系综四波混频过程产生量子关联多光束和实现位相锁定的理论与实验研究

发布时间：2018-12-26 16:55

【摘要】：多关联光束甚至多组份纠缠态不仅对于量子效应的验证还是对于量子技术的未来应用都是非常重要的,它们本身既是量子光学与原子分子物理的一个重要研究课题,又是探索这些研究方向不可或缺的工具。非局域性和量子纠缠等量子现象的验证都需要用到多组份纠缠态,因此制备多关联光束和多组份纠缠态是一项非常重要的研究课题。本论文主要介绍以下四个工作:(1)我们采用相干调制锁定技术实现了一个非线性干涉仪的位相锁定。相比于以前的锁定技术,我们主要有两方面的创新:(A)锁定了三束光之间的相对相位,以前的都是两束光情况;(B)锁定了一个非线性干涉仪的内部相位。(2)我们在理论上讨论了一个实验上容易实现的级联四波混频过程产生三组份纠缠态的可能性。我们通过计算三束光的协方差矩阵和纠缠判据的违反来证实系统中确实存在三组份纠缠态,例如两条件纠缠判据,单条件纠缠判据,最优单条件纠缠判据,部分转置保持正定判据。我们还用Duan-Giedke-Cirac-Zoller判据和部分转置保持正定判据去分析系统中可能存在的两组份纠缠。我们发现三组份纠缠和两组份纠缠中的两对在全增益空间内都是存在的。在不同纠缠判据下的纠缠性质被详细的讨论。我们的结果为基于级联四波混频过程的多组份纠缠的实现和应用开辟了道路。(3)我们理论上刻画了产生于级联四波混频过程中的多关联光束中的成对关联。在这个系统里成对量子关联可以被强度差压缩度所刻画。在不同级联四波混频过程中的所有成对的量子关联都被详细的讨论并且预测了其中的排斥效应。我们也把这些理论预测应用到实验上,发现理论和实验在一定程度上是吻合的。我们的研究为级联四波混频过程中量子态的分类和应用开辟了道路。(4)基于一个空间结构的四波混频过程,我们实验上实现了多模量子光源的一步集成。在这个过程中,注入光被放大,三个探测光和两个闲置光同时被产生,测量的四光和六光之间的强度差压缩度分别为-4.1±0.1 dB和-4.7±0.1 dB。产生的关联多光束空间上是自然分离的,这对于量子通讯是非常重要的。我们的方案紧凑,简单,相位不敏感,非常容易集成到大尺度的量子关联模式。
[Abstract]:Multi-correlated beams and even multi-component entangled states are very important not only for the verification of quantum effect but also for the future application of quantum technology. They are an important research topic in quantum optics and atomic and molecular physics. It is also an indispensable tool to explore these research directions. Multicomponent entangled states are required for the verification of nonlocality and quantum entanglement, so the preparation of multi-correlated beams and multi-component entangled states is a very important research topic. This paper mainly introduces the following four works: (1) We use coherent modulation locking technique to realize phase locking of a nonlinear interferometer. Compared with the previous locking technology, we mainly have two innovative: (A) locked the relative phase between the three beams of light, the previous two beams of light; (B) locks the internal phase of a nonlinear interferometer. (2) We theoretically discuss the possibility of a three-component entangled state generated by a cascaded four-wave mixing process that is easily realized experimentally. By calculating the covariance matrix of three beams of light and the violation of entanglement criterion, we prove that there are three components of entangled states in the system, such as two-condition entanglement criterion, single-condition entanglement criterion and optimal single-condition entanglement criterion. The partial transpose maintains a positive definite criterion. We also use Duan-Giedke-Cirac-Zoller criterion and partial transpose preserving positive definite criterion to analyze the possible entanglement of two components in the system. We find that two pairs of three-component entanglement and two-component entanglement exist in full gain space. The entanglement properties under different entanglement criteria are discussed in detail. Our results open the way for the realization and application of multicomponent entanglement based on cascaded four-wave mixing process. (3) We characterize the pairwise correlation of multi-correlation beams generated in cascade four-wave mixing process theoretically. In this system, the pairwise quantum correlation can be described by the intensity difference squeezing degree. All pairwise quantum correlations in different cascaded four-wave mixing processes are discussed in detail and their repulsive effects are predicted. We also apply these theoretical predictions to experiments and find that the theory is consistent with the experiment to some extent. Our research opens the way for the classification and application of quantum states in the cascade four-wave mixing process. (4) based on a space-structured four-wave mixing process, we have experimentally realized the one-step integration of multi-mode quantum light sources. During this process, the injected light is amplified and three probe and two idle light are generated simultaneously. The intensity difference compressibility between the four and six light measured is -4.1 卤0.1 dB and -4.7 卤0.1 dB., respectively. The resulting multiple beams are naturally separated in space, which is very important for quantum communication. Our scheme is compact, simple, phase insensitive and easy to integrate into large scale quantum correlation models.
【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O431.2

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