Zhishan Gao
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View article: Design of an extreme ultraviolet lithography objective system based on off-axis conic surfaces including a starting point and visualized full-field aberration correction
Design of an extreme ultraviolet lithography objective system based on off-axis conic surfaces including a starting point and visualized full-field aberration correction Open
In this paper, we propose a design method for an extreme ultraviolet lithography (EUVL) objective system based on off-axis conic surfaces and a visualized full-field aberration correction derived from nodal aberration theory. We divide the…
View article: Dynamic compensation of modulation aberration of high-aspect-ratio composite trenches via BP neural network for topography measurement
Dynamic compensation of modulation aberration of high-aspect-ratio composite trenches via BP neural network for topography measurement Open
In coherence scanning interferometry (CSI) for high-aspect-ratio (HAR) micro-structures, modulation aberrations induced by trench hinder accurate measurement on their bottom. In order to solve this problem, current methods primarily addres…
View article: Three-dimensional topography reconstruction method for non-uniform under-sampled vertical scanning micro-interferometry
Three-dimensional topography reconstruction method for non-uniform under-sampled vertical scanning micro-interferometry Open
Low-coherence scanning interferometry (LCSI) is a high-precision method for 3D surface topography measurement. However, the non-uniform spatial distribution of sampling points and the size of sampling intervals jointly constrain the measur…
View article: Starting-point design method for unobscured four-mirror reflective imagers based on multi-aberration evaluation
Starting-point design method for unobscured four-mirror reflective imagers based on multi-aberration evaluation Open
A multi-aberration evaluation function is proposed based on the confocal conic mirrors, aiming to search for the optimal starting-point of unobscured four-mirror reflective imagers. Typical aberrations in the off-axis confocal conic system…
View article: Computational Adaptive Optics for HAR Hybrid Trench Array Topography Measurement by Utilizing Coherence Scanning Interferometry
Computational Adaptive Optics for HAR Hybrid Trench Array Topography Measurement by Utilizing Coherence Scanning Interferometry Open
High aspect ratio (HAR) sample-induced aberrations seriously affect the topography measurement for the bottom of the microstructure by coherence scanning interferometry (CSI). Previous research proposed an aberration compensating method us…
View article: Topographic spatial resolution enhancement of coherence scanning interferometry based on extended Fourier optics model through pupil modulation
Topographic spatial resolution enhancement of coherence scanning interferometry based on extended Fourier optics model through pupil modulation Open
Lateral resolving power is a critical performance metric in coherence scanning interferometry (CSI) for characterizing surface form and texture. Pupil modulation enhances lateral resolving power by reducing the Airy disk size within the po…
View article: Co-phase error detection of segmented mirrors based on polarization-multiplexing multi-wavelength dynamic interferometry
Co-phase error detection of segmented mirrors based on polarization-multiplexing multi-wavelength dynamic interferometry Open
View article: Research on modulation aberration numerical correction method of interference signals for high aspect ratio samples utilizing coherence scanning interferometry
Research on modulation aberration numerical correction method of interference signals for high aspect ratio samples utilizing coherence scanning interferometry Open
Coherence scanning interferometry (CSI) is a non-destructive method for measuring the microstructure surface topography, but it fails to retrieve the bottom topography because the detection light is blocked by the sidewalls of the high asp…
View article: Topographic Spatial Resolution Enhancement of Coherence Scanning Interferometry Through Pupil Modulation
Topographic Spatial Resolution Enhancement of Coherence Scanning Interferometry Through Pupil Modulation Open
Topographic spatial resolution is a metrological characteristic that describes the ability of a surface topography measuring instrument to distinguish closely spaced surface features. The optical and the topographic spatial resolutions are…
View article: Topographic Spatial Resolution Enhancement of Coherence Scanning Interferometry Through Pupil Modulation
Topographic Spatial Resolution Enhancement of Coherence Scanning Interferometry Through Pupil Modulation Open
Topographic spatial resolution is a metrological characteristic that describes the ability of a surface topography measuring instrument to distinguish closely spaced surface features. The optical and the topographic spatial resolutions are…
View article: Active-compensation of systematic error for the 1000 mm aperture flat interferometer
Active-compensation of systematic error for the 1000 mm aperture flat interferometer Open
Large-aperture elements would induce unnegligible systematic errors due to material inhomogeneity, manufacturing or gravity, that are difficult to correct in an extreme large aperture flat interferometer and result in reference wavefront d…
View article: Topography reconstruction of high aspect ratio silicon trench array via near-infrared coherence scanning interferometry
Topography reconstruction of high aspect ratio silicon trench array via near-infrared coherence scanning interferometry Open
Topography measurement of high aspect ratio trench array using coherence scanning interferometry presents significant challenges because the numerical aperture of detection light is constrained by the trenches. Altering the detection light…
View article: Quantitative Evaluation of the Batwing Effect on Depth Measurement in Coherence Scanning Interferometry for Rectangular Gratings
Quantitative Evaluation of the Batwing Effect on Depth Measurement in Coherence Scanning Interferometry for Rectangular Gratings Open
Coherence scanning interferometry (CSI) is a widely used non-contact method for measuring areal surface topography. The calculation of groove depth typically employs the ‘W/3 rule’ specified in ISO 5436-1. However, the batwing effect cause…
View article: Calibration method of topography error of white light interferometry on curved surface sample measurement
Calibration method of topography error of white light interferometry on curved surface sample measurement Open
白光显微干涉术在平面阶跃型结构的形貌测量中具有显著优势。但在测量斜率变化的曲面样品时,由于物镜数值孔径的限制,样品表面反射光随着斜率的增大而减弱,干涉信号对比度降低,导致形貌测量结果的误差增大。基于表面传递函数(surface transfer function, STF)计算得到的逆滤波器可用于校正曲面样品的形貌测量误差,但现有方法的逆滤波器增益受限,无法有效提升频谱中的高频信号,对最大可测量斜率的提升有限。针对该问题,提取由白光干涉仪特性参数计算获得的虚拟STF的模作为…
View article: Absolute test technology for rotation and translation interference based on lightweight calibration mirror
Absolute test technology for rotation and translation interference based on lightweight calibration mirror Open
光学干涉绝对检验技术能够实现参考面和待测面面形的有效分离,是对干涉仪进行精度标定的有效手段。面向大口径平面干涉仪的校准需求,旋转平移法仅需一块透射平晶和一块反射平晶,避免了额外加工第3块平晶的成本和难度。但随着口径的增大,自重和支撑使得反射平晶在平移和旋转多种状态下的变形较大,继而影响绝对检验精度。提出设计轻量化的校准反射镜作为反射平晶,采用旋转平移法实现大口径干涉仪的绝对检验。以Φ 1 500 mm平面干涉仪作为标定需求,采用碳化硅作为校准反射镜材料,以三角…
View article: A camera array based reconstruction method for limited observation windows projection in three-dimensional flame chemiluminescence tomography
A camera array based reconstruction method for limited observation windows projection in three-dimensional flame chemiluminescence tomography Open
Three-dimensional(3D) flame chemiluminescence tomography (FCT) is realized in multi-direction and multi-angle using traditional iterative algorithms. However, 3D-FCT is often challenged by insufficient sampling data because of the limited …
View article: A Broadband Achromatic Alvarez Metalens
A Broadband Achromatic Alvarez Metalens Open
View article: Generalized phase profile design method for tunable devices using bilayer metasurfaces
Generalized phase profile design method for tunable devices using bilayer metasurfaces Open
Tunable devices based on bilayer metasurfaces have attracted researchers’ attention in recent years for their accurate tuning abilities and high integration. In tunable devices such as tunable beam splitters and Alvarez metalenses, opposit…
View article: Differentiation of breast tissue types for surgical margin assessment using machine learning and polarization-sensitive optical coherence tomography
Differentiation of breast tissue types for surgical margin assessment using machine learning and polarization-sensitive optical coherence tomography Open
We report an automated differentiation model for classifying malignant tumor, fibro-adipose, and stroma in human breast tissues based on polarization-sensitive optical coherence tomography (PS-OCT). A total of 720 PS-OCT images from 72 sit…
View article: Synchronous phase-shifting microscopic interference focal detection method based on wave aberration criteria
Synchronous phase-shifting microscopic interference focal detection method based on wave aberration criteria Open
为了实时准确地将激光直写系统中经直写物镜聚焦的光斑定位于待加工元件表面，提出了一种基于波像差判据的同步相移显微干涉检焦方法，实现了对离焦量的实时检测与调整。在直写系统中引入检焦光路，与直写光路共享同一物镜，构建Linnik型同步相移显微干涉检焦系统，提取包含离焦量的波面相位信息；再从大数值孔径（NA）的物镜波像差数据中解析出离焦量的大小与方向。仿真结果验证了基于波像差判据的离焦计算方法的正确性，NA≥0.5时，离焦探测灵敏度可达4 nm, 通过实…
View article: Construction of freeform mirrors for an off-axis telecentric scanning system through multiple surfaces expansion and mixing
Construction of freeform mirrors for an off-axis telecentric scanning system through multiple surfaces expansion and mixing Open
View article: Automated fast computational adaptive optics for optical coherence tomography based on a stochastic parallel gradient descent algorithm
Automated fast computational adaptive optics for optical coherence tomography based on a stochastic parallel gradient descent algorithm Open
The transverse resolution of optical coherence tomography is decreased by aberrations introduced from optical components and the tested samples. In this paper, an automated fast computational aberration correction method based on a stochas…
View article: Hilbert transform-based envelope substitution method for non-uniform sampling signal correction in white-light interferometry
Hilbert transform-based envelope substitution method for non-uniform sampling signal correction in white-light interferometry Open
White-light scanning interferometry is an effective and widely used technology for measuring the microscopic three-dimensional morphology of an object. However, it is easily affected by external disturbances and appears to have a non-unifo…
View article: Profile measurement of red blood cells based on simultaneous phase-shifting microscopic interference
Profile measurement of red blood cells based on simultaneous phase-shifting microscopic interference Open
血红细胞的形貌特征是医学领域对多种疾病进行预防和诊断的一项重要指标，提出一种同步移相显微干涉法实现对血红细胞形貌的动态测量。搭建了透射式显微干涉成像系统，测量了100 μm内径模拟微血管内、名义直径为7 μm～8 μm、高度最大值为2 μm的新西兰兔血红细胞，针对血红细胞所处的微血管环境提出了基于微血管相位相减的血红细胞形貌提取方法和成像放大率校正方法，实验得到模拟微血管内的血红细胞平均直径7.757 μm和平均最高高度2.022 μm，验证了本方法具有在体定量测量血红细胞…
View article: Geometric characteristics and error analysis of standard spherical lens
Geometric characteristics and error analysis of standard spherical lens Open
标准球面透镜是斐索型干涉仪的核心器件，综述标准球面透镜的几何特性和误差。分析标准球面透镜在干涉照明光路和成像光路中的作用，重点介绍并实验验证了球面干涉成像的R-sinθ几何特性关系模型，给出了采用Q非球面实现非球面分裂的新型设计方法，以及2片式非球面标准球面透镜结构的实例，概述了针对小F数标准球面透镜球面干涉腔中的待测球面调整误差和移相空间非均匀性误差的研究成果，介绍了校正球面干涉腔中误差的波面差分算法，指出在近标准球面透镜焦点位置…
View article: Construction method through multiple off-axis parabolic surfaces expansion and mixing to design an easy-aligned freeform spectrometer
Construction method through multiple off-axis parabolic surfaces expansion and mixing to design an easy-aligned freeform spectrometer Open
The classic Czerny-Turner spectrometer consists of a plane grating and two spherical mirrors. The optical path geometry adopted for incident and grating dispersed light is off-axis reflection, so the spherical collimating and focusing mirr…
View article: Review of microsphere optical microscopy for super-resolution imaging and metrology
Review of microsphere optical microscopy for super-resolution imaging and metrology Open
受衍射极限的影响，传统光学显微镜的分辨率最高约为波长的一半，突破衍射极限，获得更高的成像分辨率是近年来显微成像领域的研究热点。相比于其他超分辨显微成像方式，基于微球透镜的超分辨显微成像方式具有简单直接、免标记等优点。主要介绍国内外研究团队将微球与传统的光学显微镜结合实现超分辨显微成像的研究进展，从微球透镜参数选择、成像方案、成像分辨率、成像视场及成像机理等多角度进行总结与比对；并结合课题组工作，介绍了将微球透镜与干涉显微技术相结合的三维超分辨检测技术，阐述了Linnik型与…
View article: Generalized shift-rotation absolute measurement method for high-numerical-aperture spherical surfaces with global optimized wavefront reconstruction algorithm
Generalized shift-rotation absolute measurement method for high-numerical-aperture spherical surfaces with global optimized wavefront reconstruction algorithm Open
In this paper, a generalized shift-rotation absolute measurement method is proposed to measure the absolute surface shape of high-numerical-aperture spherical surfaces. Based on the wavefront difference method, the high order misalignment …
View article: Detection of the binary optical element based on ptychography
Detection of the binary optical element based on ptychography Open
Due to the extremely high diffractive efficiency and flexible design freedom, binary optical element can realize specific function in the optical system in comparison with the traditional refractive optical element. Ptychography, which is …
View article: Correction of axial distance error in ptychography based on image information entropy
Correction of axial distance error in ptychography based on image information entropy Open
Ptychography provides an extremely robust and highly convergent algorithm to reconstruct the specimen phase with a wide field of view. The resolution and accuracy of ptychography are severely restricted by the uncertainty of the position e…