4F简并腔输出光场空间相干特性分析  

Spatial Coherence Characteristics of 4F Degenerate Cavity Optical Field

作　　者：唐健豪 张笑琪 张艳丽[1] 张国文[1] 王瑞峰 陈子昂 朱健强[1] Tang Jianhao;Zhang Xiaoqi;Zhang Yanli;Zhang Guowen;Wang Ruifeng;Chen Ziang;Zhu Jianqiang(National Laboratory on High Power Laser and Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院上海光学精密机械研究所高功率激光物理联合实验室,上海201800 [2]上海科技大学物质科学与技术学院,上海201210

出　　处：《中国激光》2024年第23期17-22,共6页Chinese Journal of Lasers

基　　金：中国科学院战略先导科技专项A类(XDA25020203,XDA25020301)。

摘　　要：从菲涅耳-基尔霍夫衍射理论出发,分析4F简并腔的空间相干特性及纵模特性。利用杨氏双孔实验测量其空间相干特性。假设4F简并腔输出光场为谢尔模型,从输出光场的近、远场的光强出发,给出了谢尔模型的空间相干度分布,结果表明在频谱面插入圆形光阑时,4F简并激光腔的输出光场可以使用谢尔模型近似。Objective The Hermite-Gauss eigensolution of confocal or spherical cavities significantly affects lasers,and the transmission laws of these cavities have been extensively investigated.When multiple transverse-mode oscillations are present,lasers are partially spatially coherent.In 1969,Arnuaud proposed a range of degenerate cavities that can yield a low-coherence laser output.In 2013,Nixon et al.experimentally demonstrated that a 4F degenerate cavity can generate low-coherence lasers,which can effectively reduce the scattering contrast while simultaneously controlling the diaphragm size in the intracavity spectrum to achieve a spatially coherent optical-field output of the 4F degenerate cavity.In 2015,Chriki et al.demonstrated that altering the geometry of the diaphragm in the spectral plane of the cavity can alter the shape of the spatial-coherence function of the optical field output.These studies showed that a 4F degenerate cavity can generate low-spatial-coherence lasers with adjustable spatial coherence to achieve scatter suppression during imaging.Most studies analyzed the 4F degenerate cavity’s output field using a multitransverse mode laser.This approximation explains the spatial properties of the 4F degenerate cavity’s output field.However,some conflicts exist,such as the shape of the beam output from the 4F degenerate cavity changing during transmission,whereas the shape of the Hermite-Gauss beam remains constant during linear transmission.Therefore,the transverse light-field distribution in a 4F degenerate cavity must be re-analyzed.Methods A 4F degenerate cavity laser is constructed with circular diaphragms of varying sizes on its spectral plane.The near and far fields are measured in different cases using a charge-coupled device(CCD)and spatial coherence distributions are measured at various locations within the optical field.This study analyze the transverse and longitudinal modes in a 4F degenerate cavity using the Fresnel-Kirchhoff diffraction equation.Finally,the light intensity and coherence

关 键 词：激光器 部分相干光 简并腔 谢尔模型 

分 类 号：TN241[电子电信—物理电子学]