阵列式径向偏振共焦扫描超分辨测量方法与理论研究

To address the problem of array confocal system's resolution decline which is caused by the system inherent coupling superposition and panning effects, we propose a high-density, high-resolution and high noise immunity of the array confocal scanning and sensing method. Research: 1) Establish diffracted light field imaging model under polarized light of array radial polarization based on vector diffraction theory, improve the ability to detect three-dimensional space of the system by modulating the optical field distribution characteristics of point source array. 2) Dynamic change the grating structure through the spatial light modulator based on the blazed characteristics, in order to realize the collimating light deflection in succession and complete a wide range of high-density arrays of confocal scanning measurement, while suppressing the point light source array optical coupling effects between adjacent. 3) Present a method of collecting continuous phase pupil filter optimization of optical symmetrical shift focus, in order to improve the properties of the focusing spot of the light intensity distribution through the polarization mode conversion method, improve the ability to distinguish the three-dimensional system, expand the measurement range and suppress common mode interference. 4) There are three main technical indicators: the axial resolution is 20nm, the horizontal scanning interval is 0.2um, an imaging contains 225 points. If the project is complete, we can solve the contradiction among high-density measurements, wide field of view, and three-dimensional resolution, they all exist in an array of confocal system; the project enables confocal system array, digitization, and expand its application areas.

针对阵列共焦系统中固有的耦合叠加效应和平移效应所引起的系统分辨力下降的问题，提出一种具有高密集度、高分辨力和高噪声抑制能力的阵列式共焦扫描传感方法。研究内容：1）建立基于矢量衍射理论的阵列径向偏振光照明下衍射光场成像模型，通过调制阵列点光源光场分布特性，提高系统三维空间探测能力；2）基于闪耀特性通过空间光调制器动态改变光栅结构，以实现准直光连续偏转和高密集度阵列大范围共焦扫描测量，同时抑制点光源阵列相邻光路之间的耦合效应；3）提出一种收集光路对称移焦的连续相位光瞳滤波器优化方法，并通过偏振模式转换方法改善聚焦光斑光强分布特性，提高系统的三维分辨能力扩大测量范围，同时抑制共模干扰。4）主要技术指标，轴向分辨力为20nm，横向扫描间隔0.2um，一次成像225个点。该项目的完成可解决阵列共焦系统中存在的高密集测量、宽视场与三维分辨力之间的矛盾；使共焦系统阵列化、数字化，并拓展其应用领域。

为了提高共焦显微测量系统的测量扫描效率，同时兼顾系统三维探测分辨力，本课题提出了阵列式径向偏振共焦扫描超分辨测量方法与理论研究。主要研究内容：1）利用矢量衍射理论，针对大数值孔径显微物镜成像建立了共焦显微系统在径向偏振光照明下，衍射光场成像的数学模型，揭示了大数值孔径物镜对径向偏振照明光的聚焦成像规律，并在此基础上，研究了光瞳滤波器对径向偏振聚焦场的调制特性，理论分析和实验表明，利用径向偏振照明可有效提高系统横向分辨力，但在一定程度上降低了系统的轴向分辨力；2）提出了闪耀光栅偏转扫描方法，利用空间光调制器模拟闪耀光栅，通过改变闪耀光栅周期可实现光束的偏转，从而实现共焦系统的横向扫描，实验表明该方法可以实现阵列光束的高密集连续扫描，有效提高系统的扫描测量效率；3）针对径向偏振光改善共焦系统横向分辨力但同时降低轴向分辨力的问题，提出了在收集光路部分加入移焦相位光瞳滤波器，以实现双路差动共焦显微测量，该方法可实现在不改变横向分辨力的前提下，使原有系统的轴向分辨力提高2倍，该方法可弥补由径向偏振光引起的轴向分辨力下降的问题，同时可抑制系统光强变化等共模干扰。实验结果表明，该方法可有效提高系统的三维分辨力，且能够实现阵列共焦高效率扫描测量，该方法可应用于微结构器件的三维形貌测量，具有非常重要的实际应用价值和广阔的应用前景。