基于涡旋光的三种气辉(极光)光谱线型的比较研究

Comparative study of three airglow (aurora) spectral line profiles based on vortex light

  • 摘要: 对被动遥感探测高层大气风场所使用的高斯光谱线型、洛伦兹线型与佛克托线型三种线型的气辉(极光)光源引入涡旋光因子后,从理论上导出了三种线型涡旋光表达式,模拟得到三种气辉(极光)涡旋光线型的调制图像,三种线型随拓扑荷数的变化出现不同程度的消光:高斯型涡旋光绕轴旋进一周相位改变2πl,整体呈螺旋形,中心消光部分及相位随拓扑荷数l增加而增大;洛伦兹型涡旋光以横轴分布方向为主要的消光方向。随着l增加光强减弱,以间断式进行中心消光,具有螺旋空间相位结构;佛克托型涡旋光的花样对称分布于横向与纵向两侧,顶部呈“V”型沿-z方向消光。给出三种线型涡旋光的干涉强度与光程差、拓扑荷数的关系式,模拟得到三种线型涡旋光的干涉条纹的3D图,发现不同拓扑荷数下空间光谱强度产生不同的叉形结构:随着涡旋相位的改变,原有空间分布发生变化,整体从光强最大处开始向两侧延伸并挤压,分数拓扑荷数下涡旋相位挤压和错位影响更大。实验结果发现高斯型涡旋光的亮环数目与拓扑荷数l相同,拓扑荷数l每增加1,则总拓扑相位就会增加2π,束腰半径也随之增加。

     

    Abstract: Adding the vortex factors to the Gaussian, Lorenz, and Voigt airglow (aurora) light spectrum profiles of the for the upper atmospheric wind measurement, the vortex expressions of the three profiles of airglow (aurora) light sources are derived theoretically. The three profiles of airglow (aurora) with vortex light are simulated, and it is found that the extinction of the three profiles of light sources varies with the topological charge number l. The Gaussian vortex light rotates around the axis and the phase changes by 2πl, and the central extinction part and phase increase with the increase of l. The main extinction direction of Lorenz vortex is the transverse axis distribution direction. With the increase of l, the light intensity decreases, and the center extinction is carried out in discontinuous mode, which has a spiral spatial phase structure. Voigt vortex light profile is symmetrical on both the transverse and longitudinal sides, and the top is V-shaped extinction along the -z direction. The expressions are derived between the interference intensity of the three profile of vortex light, optical path difference and topological charge number, and the 3D diagram of the interference fringe of the three profiles of vortex light is simulated, and it is found that the spatial spectral intensity produces different fork structures under different topological charge number: with the change of vortex phase, the original spatial distribution changes, and the whole extends and extrudes from the maximum light intensity to both sides, and the influence of vortex phase extrude and dislocation is greater under fractional topological load. The experimental results show that there are fringes outside the bright ring of the Gaussian vortex light with the same topological charge number l, and the total topological phase will increase 2π and the beam waist radius will increase with each increase of topological charge number l by 1.

     

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