原子相干晶格带隙空间光调制研究

The researchers all over the world has focused theirs attention on the propagation properties of spatial beam, both in theory and experiment. In multi-level atomic vapor medium, with the quantum control methods we study the modulation of spatial beam based on the nonlinear Kerr effect enhanced by dressed effect and 2D atomic coherent lattice state:. 1. Through atomic coherence method, the competition between the cubic and quintic nonlinearities as well as the concomitant gain and loss can be adjusted, and the propagation properties of azimuthally-modulated vortex solitons can be investigated with different the number of topological charge. The characteristics of talbot effect and PT-symmetric in a coherent atomic medium also can be investigated.. 2. By the experimental system with strong pulse lasers, electromagnetically induced lattice (EIL) was created by adjusting the orientations of electromagnetically induced grating (EIG), with which the 2-dimensional spatial gap soliton of FWM signal is demonstrated.. 3. We demonstrate the photonic Floquet topological insulator (PFTI) in an atomic vapor with nonlinear susceptibilities. The appearance of Dirac cones and the formation of PFTI is strongly affected by the nonlinear susceptibilities; i.e. the PFTI can be shut off by the third-order nonlinear susceptibility and re-opened up by the fifth-order one.

空间光传输特性的研究不论在理论还是实验上都是该领域研究的热点问题。本课题拟从理论和实验两个方面在多能级原子系综介质中，基于缀饰增强克尔效应和二维晶格态，通过量子调控手段对空间光特性进行以下方面的研究：. 1. 通过原子相干技术调节在双光子共振位置处三五次非线性以及伴随的增益和损耗之间的竞争，研究不同参数条件下光信号携带不同拓扑荷时形成光涡旋的特性、Talbot效应以及介质的PT对称性特性。. 2. 利用强脉冲光实验系统，形成了具有二维周期性折射率分布的电磁诱导晶格，获得了多参量可调控的四波混频信号二维空间带隙孤子。. 3. 基于周期性非线性极化率，我们在原子气体中实现了光子拓扑绝缘体。狄拉克光锥和光子拓扑绝缘体的形成会受到非线性极化率的显著影响，如三阶非线性极化率会湮灭光子拓扑绝缘体，而五阶会使得光子拓扑绝缘体重新形成。

本课题从理论和实验两个方面在多能级原子系综介质中，基于缀饰增强克尔效应和二维晶格态，通过量子调控手段对空间光特性进行以下方面的研究：.1. 通过三五次非线性以及伴随的增益和损耗之间的竞争，研究不同参数条件下光信号携带不同拓扑荷时形成光涡旋的特性。发现诱导出的光涡旋会受到入射光所携带的拓扑荷数、光斑瓣数以及光束大小显著影响。但总的总拓扑荷是守恒不变的。.2. 通过原子相干技术调节在双光子共振位置处三五次非线性以及伴随的增益和损耗之间的竞争，研究真正意义上的非线性Talbot效应。.3. 原子相干可以在原子气体中诱导出电磁光晶格，研究该光晶格抑制增强位置处的带隙结构及介质的PT对称性特性。.4. 在原子气体与电介质的接触面上，研究空间调制后的菲涅耳无衍射光演化等。