微环谐振腔中点光源产生轨道角动量的特性

Properties of a point light source in microring resonator with orbital angular momentum

提升量子光源在量子信息处理方面的编码容量是量子技术发展亟需解决的问题。轨道角动量作为光子一个独特的自由度,其空间模式分布会形成无限维完备的希尔伯特空间正交解,因此利用光子的轨道角动量进行编码可以极大地提高信息处理的容量,是高维量子信息处理的重要资源。具有二能级系统的量子光源可以等效成点光源,在微纳尺度下对量子光源进行调制产生轨道角动量是拓展片上集成量子光源编码维度的有效方法之一。主要探讨了点光源在微环谐振腔中产生轨道角动量叠加态的特性。首先介绍了角向光栅对微环谐振腔中点光源产生轨道角动量的调制机理;然后研究了微环谐振腔的腔量子电动力学效应对点光源辐射子的辐射速率和收集效率的影响,并对单光子纯度进行了分析;最后研究了点光源产生轨道角动量叠加态的电场分布、相位分布及矢量偏振特性,不仅分析了微环谐振腔中不同位置的点光源对腔模及轨道角动量的影响,还对出射轨道角动量叠加态的纯度进行了详细分析。该研究为集成轨道角动量光量子器件的发展提供了有效的方法,对进一步了解微纳尺度下产生轨道角动量的机理和性质有良好的促进作用。

To promote the coding capacity of quantum light sources in quantum information processing is an urgent problem to be solved in the development of quantum technology.As a unique degree of freedom for photons,the spatial pattern distribution of orbital angular momentum will form an infinitedimensional orthogonal solution in Hilbert space.Therefore,encoding with the orbital angular momentum of photons can greatly increase the capacity of information processing and is an important resource for high dimensional quantum information processing.A quantum light source with a two-level system can be equivalent to a point light source,and modulating the quantum light source to generate orbital angular momentum at the micro-nano scale is one of the effective ways to expand the coding dimension of on-chip integrated quantum light source.This article mainly discusses the properties of the superposition state of orbital angular momentum generated by point light source in micro-ring resonator.Firstly,the modulation mechanism on the orbital angular momentum generated by the point light source in the microring resonator with angular gratings is introduced.Then,the influence of the cavity quantum electrodynamics effect of the microring resonator on the radiation rate and collection efficiency of the point light source emitter is investigated,and the single photon purity is also discussed.Finally,the electric field distribution,phase distribution and vector polarization characteristics of the superposition state of orbital angular momentum produced by the point light source are investigated.Not only the effect of the point light source at different positions in the microring cavity on the cavity mode and the properties of orbital angular momentum,but also the mode purity of the single-photon orbital angular momentum states is analyzed in detail.This research provides an effective method for the development of integrated optical quantum devices carrying orbital angular momentum,which will promote the further understanding of the mechanism and properties of the orbital angular momentum generated at the micro-nano scale.