基于偏振光相位调制的超衍射极限空间结构光研究  

Sub-diffraction-limit spatially structured light pattern based on polarized beam phase modulation

作　　者：袁强[1] 赵文轩[1] 马睿[2] 张琛[1] 赵伟[1] 王爽[1] 冯晓强[1] 王凯歌[1] 白晋涛[1] 

机构地区：[1]西北大学光子学与光子技术研究所,国家光电技术与功能材料重点实验室培育基地,陕西光电技术实验室,国家光电技术与纳米功能材料和应用国际研究中心,西安710069 [2]西安工业大学光电学院,西安710021

出　　处：《物理学报》2017年第11期18-26,共9页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:11504294);国家自然科学基金面上项目(批准号:61378083);国家自然科学基金重大研究计划培育项目(批准号:91123030);科技部中美合作项目(批准号:2011DFA12220);陕西省自然科学基础研究计划青年人才项目(批准号:2016JQ1030);陕西省自然科学基金(批准号:14JS106,2013SZS03-Z01)资助的课题~~

摘　　要：具有超衍射极限尺寸的空间结构光在远场超分辨成像、光镊、微纳米加工等领域都有着重要的应用.本文基于偏振光的相位调制原理,结合光学实验与光场数值模拟开展了在空间生成具有超衍射极限尺寸的空间结构光的研究.首先设计了一种兼备圆形π与涡旋形2π相位板特点的新型相位板,并且实验观察到了高数值孔径系统中新型相位板调制圆偏振高斯光的焦点处的空间结构光形貌.随后通过结合矢量衍射积分理论的数值模拟,得出了一种具有超衍射极限尺寸、且同时呈现中心对称与轴对称的空间结构光.最后,本文详细讨论分析了新型相位板调制圆偏振光、线偏振光、径向偏振光以及角向偏振光所获得的空间结构光分布特点.结果显示,圆、线、径向与角向偏振条件下得到的空间结构光横向最小暗斑的半高全宽分别为0.31λ,0.32λ,0.24λ和0.36λ;在光轴上,线、径向与角向偏振光情况下的中心暗斑的半高全宽分别为0.8λ,0.78λ,0.76λ,而圆偏振光在轴向方向没有电矢量分布.The sub-diffraction-limit spatially structured light patterns have attracted more and more attention for their impor- tant applications in many frontier scientific fields. The present paper aims at developing sub-diffraction-limit spatially structured beam patterns which might have great potential to improve the light performance in fields such as super resolution imagery, optical tweezer, miero/nano lithography, etc. Here, a variety of spatially structured beam patterns are obtained by the phase modulation of polarized beams and studied in detail experimentally and numerically. Firstly, a new kind of phase plate, which combines the merits of circular π and vortex 2π phase plates, is proposed based on the wave front design; it is composed of two spiral-shaped phase plates with their phases changing from O to 2π and -π to π, respectively. Later, the phase plate is applied to the circularly polarized Gaussian beam modulation in a high NA system. By combining a self-made circular π with a commercial vortex 2π phase plate, the designed new phase plate is implemented in the experiment. The morphology of the spatially structured light pattern, which is generated on the focal plane, is observed by a CCD camera in the experiment. The beam pattern presents a donut shape on the focal plane, while the dimension of the donut-shaped pattern becomes smaller as the imaging plane axially deviates from the focal plane. It is found that the beam patterns captured in experiment highly consist with the numerical simulation results carried out by the vectorial diffraction integral theory. It can be deduced that the spatially structured beam is capillary-shaped. Meanwhile, at the two ends of the capillary-shaped beam, the inner diameter is smaller than the diffraction limitation. Furthermore, the structured beam pattern presents a spatial voxel distribution with center and axis symmetry. Finally, the characteristics of the spatially structured beam patterns, which are generated by modulating circular, linear, radial and azimuth

关 键 词：相位调制 超衍射极限 结构光 衍射积分理论 

分 类 号：O436[机械工程—光学工程]