【作者】 唐磊；

【导师】 肖敏； 张勇；

【作者基本信息】 南京大学 ， 光学工程（专业学位）， 2019， 硕士

【摘要】 量子信息处理芯片能够实现对光量子体系的高精度和普适化的量子调控和量子测量,是当前量子科技革命的关键之一。目前,科学研究迫切需要扩大集成量子光路元件的功能性,增强其对量子信息处理的能力,从而推进量子信息技术的应用。手性量子光子是近几年发展起来的一个新研究领域,其主要研究在纳米光学结构器件中光场与量子发射器手性耦合现象及其应用。在纳米结构中,光场由于受到很强的束缚会产生沿着传播方向的电场成分,从而表现出局域的手性圆偏振态分布,即光场的偏振态与传播方向有关;进而导致光场与量子发射器的耦合强度也依赖于光的传播方向。基于手性量子光学和腔量子电动力学,本文研究了一种能够实现单光子信息调控的多功能手性界面,并演示了其单光子隔离和单光子定向发射功能,具体包括:ⅰ.构建了由波导、微环谐振腔和量子点组成的手性耦合系统,即手性单光子界面。使用电磁仿真方法,我们设计一种具有手性圆偏振光场分布的微环谐振腔。当光子以正方向入射时,在微环谐振腔外侧的倏逝场是近完美的左旋圆偏振光;而当光子以负方向入射时,在相同的位置处倏逝场是近完美的右旋圆偏振光。ⅱ.演示了单光子隔离功能。将量子点放置于腔壁外侧手性倏逝场很强的位置,并将其初始化后只能与左旋圆偏振光发生耦合。于是由于不同传播方向的光场与量子点的耦合强度不一致,实现了单光子隔离功能。ⅲ.演示了单光子定向发射功能。当位于腔壁外侧的量子点被泵浦在右旋圆偏振光跃迁激发态上,光子将从波导右端口出射;而当量子点被泵浦在左旋跃迁激发态上,光子将从波导左端口出射。并且光子会以长脉冲光子或Time-bin光子的形式定向发射。更多还原

【Abstract】 The photonic chips for quantum information processing can achieve high precision and universal quantum control and quantum measurement of opti-cal quantum systems,which are one of the keys to the current quantum tech-nology revolution.At present,scientific research urgently needs to expand the functionality of integrated quantum optical components and enhance its ability to process quantum information,thereby promoting the application of quantum information technology.Chiral quantum optics is a new research field developed in recent years.It mainly studies the process of chiral coupling of light and quantum emitters in nanostructures.For example,the field transversely confined in nano-optical waveguides or nano-optical fibers produces a longitudinal electric field component along the direction of propagation,exhibiting a distribu-tion of locally circularly polarized electric fields,and the polarization of the electric fields depending on the direction of propagation,which is called op-tical chirality.At the particular location in these structures,the coupling strength of the quantum emitter to the chiral electric field is also depending on the direction of light propagation.Based on chiral quantum optics and cavity quantum electrodynamics,this paper designs a multi-functional on-chip chiral interface,which can manipulate single photon information,and achieve single photon isolation and unidirectional photon emission.This paper mainly includes:i.We build the chiral single photon interface,which is a chiral coupling system consisting of a waveguide,a microring resonator,and a quantum dot.Using electromagnetic simulation methods,we designed a microring resonator with chiral circularly polarized electric field distributions.When the photon is incident in the positive direction,the evanescent field nearby the outside wall of the resonator is near perfect left-handed circularly polarized light,and when the photon is incident in the opposite direction,the evanescent field at the same position is a near perfect right-han ded circlarly polarized light.ii.We show a broadband optical isolation at the single-photon level over several gigahertz.The quantum dot is placed nearby the outside wall of the resonator and initialized to couple only with the left-hand circularly polarized light.Therefore,since the coupling strength between the light and the quantum dot in different propagation directions is inconsistent,single photon isolation is realized.iii.We show unidirectional and polarization-deterministic single-photon emis-sion.When the quantum dot is initially prepared in its excited state,it will emit a single photon into either the CW mode or the CCW one in the strong-couping regime.The exiting path of the photon is determined by the populated excited state of the QD.Therefore,by initializing the QD in a spin-selective excited state,we can realize the unidirectional emission of single photons.And the emitted photon can be a long-pulsed single photon or a time-bin single photon.更多还原