共查询到20条相似文献,搜索用时 125 毫秒
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用矢量衍射方法分析了线偏振光入射到带有三环位相型光瞳滤波器的高数值孔径物镜时,焦点的轴向和横向光强分布.数值模拟结果表明,高数值孔径物镜聚焦时需同时考虑光强的轴向和横向分布.通过加入三环位相光瞳滤波器,在实现横向超分辨的同时实现了光学系统轴向焦深扩展和轴向光强分布平坦化,并且位相调制深度变化时,会出现轴向焦移现象.对三环位相光瞳滤波器结构进行了优化,得出了优化结果.
关键词:
光学超分辨
扩展焦深
位相型光瞳滤波器
矢量衍射方法 相似文献
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轴对称矢量光束是一种空间非均匀偏振光束, 中心光强为零, 经物镜聚焦后能在焦点附近产生空间场分量. 在高变迹系数光学系统成像情况下, 与线偏光、圆偏光相比, 径向偏振光与光瞳滤波技术及图像复原技术结合, 能获得较小焦斑, 提高横向分辨力. 介绍了轴对称矢量光束的特性, 基于电偶极子辐射模型和矢量衍射理论研究了轴对称矢量光束经高数值孔径物镜聚焦后的特性, 系统介绍了基于轴对称矢量光束实现光斑紧聚焦的几种方法, 并简述了轴对称矢量光束在差动共焦超分辨成像领域的研究设想.
关键词:
差动共焦显微技术
紧聚焦
光瞳滤波
轴对称矢量光束 相似文献
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新型显微成像光谱仪系统中线阵针孔离焦研究 总被引:1,自引:0,他引:1
显微成像光谱仪技术是最近新兴的一种生物组织检测方法,它可以广泛应用在生物医学检测,疑难病症分析、预防、诊断中,已经成为当今生物组织检测领域研究的热点。提出了一种新型的基于线阵针孔阵列的激光扫描共焦显微成像光谱仪系统LP-LSCMIS方案,介绍了其工作原理及优点,讨论了该装置中线阵针孔阵列离焦对系统性能的影响,分析了离焦对生物组织荧光图像的光谱分辨和自体荧光光谱的调制深度的影响。推导出了光谱分辨和调制深度与离焦量的关系式。结果表明,离焦对仪器的性能有较大的影响,因此在装置装调时要求有更高精度的调整机构。 相似文献
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《中国光学》2020,(1)
针对大口径光学系统中像差影响超分辨效果的问题,开展泽尼克波前像差对望远超分辨成像系统性能和超分辨局部视场影响的研究。设计四区型位相光瞳滤波器,在理想光学系统出瞳处分别加入离焦、像散、彗差和球差像差,逐渐增加幅值,通过分析不同类别和幅度的波前像差下焦面光强分布变化,研究超分辨成像性能和局部视场对不同种类像差的容忍程度。结果表明,离焦可以抑制超分辨旁瓣能量,提高超分辨倍率,但对局部视场影响较大;球差可以抑制超分辨旁瓣能量,增大局部视场;像散和彗差使光斑圆对称性明显下降,其中像散对局部视场的影响较为明显;同时加入适量离焦和球差时,超分辨旁瓣能量下降,超分辨倍率提高,且不影响系统局部视场。据此设计了一个F数为10,焦距为12 m的大口径光学系统,通过合理优化球差和离焦剩余量,实现了超分辨倍率由1.21倍到1.31倍的提升,最大旁瓣峰值由0.33下降到0.30,局部视场为38.28μm。 相似文献
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提出一种新的图像复原式整形环形光横向超分辨共焦显微测量法. 该方法首先利用二元光学器件,将高斯照明光束整形为环形光束,用于初步改善共焦显微镜的横向分辨力,然后利用基于最大似然估计法(maximum likelihood estimate, MLE)的单幅图像超分辨复原技术,重建测量图像的高频信息,来进一步改善共焦显微镜的横向分辨力. 实验表明,当λ=632.8nm,N.A. =0.85时,该方法能使共焦显微镜获得优于0.1μm的横向分辨力. 利用该方法建立的横向超分辨共焦显微系统除了具有显著的超分辨效果外
关键词:
超分辨
超分辨复原
最大似然估计
共焦成像 相似文献
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In order to further improve the performance of a confocal microscope (CM) used for measurement of surface profiles and 3D microstructures, a shaped annular beam heterodyne confocal measurement method based on annular pupil filter technique and reflection confocal microscopy, is proposed to expand the measurement range and to improve the defocused property of CM. The approach proposed uses a confocal dual-receiving light path arrangement and a heterodyne subtraction of two signals received from detectors with axial offset to enable CM to be used for bipolar absolute measurement and to improve the defocused property of CM, and it uses the annular pupil filter technique to produce a binary optical shaped annular beam, which expands the measurement range by expanding the full-width at half-maximum of intensity curve received from two detectors in a heterodyne confocal microscopy system. Theoretical analyses and experimental results indicate that a shaped annular beam heterodyne microscope has a measurement range expanded from 4 to 14 μm, achieved an axial resolution of 2 nm and improved the defocused property, when ε=0.5 and NA=0.65. It can be therefore concluded that the shaped annular beam heterodyne confocal measuring method proposed is a new approach to ultraprecision measurement of surface profiles and 3D microstructures. 相似文献
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Two models have been established using the basic definitions of super-resolution characteristic parameters for normalized spot size GT and Strehl ratio ST of a three-zone lateral super-resolution pupil filter with fabrication errors to quantitatively analyze the effect of these fabrication errors on the lateral super-resolution property. These new models established to describe the analytic relationship of GTe and STe of a pupil filter with its fabrication errors and its transmission function A(ρ), phase function φ(ρ) and structural parameters directly relate the super-resolution parameters of a three-zone lateral super-resolution pupil filter to its fabrication errors to make the quantitative analyses of the effect of fabrication errors easier, thereby providing a theoretical basis for the analysis, design and fabrication of a three-zone lateral super-resolution pupil filter. The models established for GTe and STe have been used to analyze the effect of the fabrication errors of a pupil filter on its super-resolution property with a three-zone phase-only pupil filter as an example. 相似文献
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We explore the use of the Radon-Wigner transform, which is associated with the fractional Fourier transform of the pupil function, for determining the point spread function (PSF) of an incoherent defocused optical system. Then we introduce these phase-space tools to analyse the wavefront coding imaging system. It is shown that the shape of the PSF for such a system is highly invariant to the defocus-related aberrations except for a lateral shift. The optical transfer function of this system is also investigated briefly from a new understanding of ambiguity function. 相似文献
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In order to achieve a higher lateral resolution required for ultraprecision measurement of microstructural workpieces, phase-only pupil filtering differential confocal microscopy (PFDCM), a new approach is proposed based on the differential confocal microscopy (DCM), which uses a three-zone phase-only pupil filter with lateral super-resolution capability obtained through optimized design to change the distribution of DCM three-dimensional point spread function, so that the DCM lateral resolution is therefore significantly improved while its axial resolution is slightly improved. Preliminary experimental comparison and analyses indicate that, the lateral and axial resolutions of PFDCM are better than 0.2 μm and 2 nm, respectively, when wavelength of incidence laser beam , numerical aperture of measuring lens NA=0.85, and lateral spot size with a three-zone phase-only pupil filter GT=0.65. It is therefore concluded that PFDCM is a new approach to further improvement of lateral resolution in laser probe measurement systems. 相似文献
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In order to improve the spatial resolution of a confocal system, a radial birefringent pupil filter (RBPF) is introduced into a differential confocal system. RBPF consists of two polarizers with a birefringent element between them, and its pupil function is deduced from Jones matrix. The thickness and curvature radius of RBPF are optimized independently, using the first zero coordinate ratio. The pupil function is modulated by RBPF to enhance the half-width of the response function, and lateral resolution is improved when response curve is changed with the position of RBPF as well as the polarization; then axial super-resolution of the system can be guaranteed using differential confocal detection mechanism. In comparison with conventional pupil filtering technology, RBPF features high lateral resolution and can be easily produced; moreover, it also has a simple structure. Together with its low cost, RBPF provides a new way for the improvement of super-resolution of confocal system. It is indicated from theoretical analysis and preliminary experiments that the lateral resolution can be significantly improved and the measurement error is reduced by 76 nm when measuring a standard grating of period 3 μm; the axial resolution up to 3 nm has been achieved using the optimized pupil filter. In addition to its application for measurement of a small irregular surface in a limited space, the whole differential confocal system proposed can be fitted onto a coordinate measuring machine for non-contact measurement of dimensions and surface roughness. 相似文献
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用电子俘获材料实现实时图像微分 总被引:4,自引:1,他引:3
根据数学形态学的基本思想,采用离焦的卷积光学系统,利用电子俘获材料的饱和特性和图像减法功能实现图像微分,这一方案具有清晰度高、实时性,全并行性的优点,取阀和减法运算都用一片电子俘获薄膜来实现。 相似文献
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Optical systems are analyzed with three kinds of rotational symmetric pupil masks: annular Gaussian ring mask, supergaussian ring mask, and quartic phase mask. In these masks, the quartic phase mask is found to be the best one to extend focal depth. Point spread function (PSF) and Strehl ratio (SR) are used to evaluate the imaging quality of the system with different defocus parameters. Without decoding needed, the focal depth of the system with quartic phase mask is four times as deep as aberration-free system. Different from the others, it suffers no obvious loss in the light throughput and lateral resolution.With twice focal depth extension, supergaussian ring mask suffers less loss in light throughput and lateral resolution than annular Gaussian ring mask. 相似文献
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对利用微波放电直接解离Cl2生成Cl, Cl与HN3反应生成NCl(a1Δ )和NCl(b1∑)的过程进行了实验研究。得到了较强的NCl(a1Δ 和NCl(b1∑)自发辐射光谱,考察了Cl2流量和He/Cl2配比对NCl(a1Δ 和NCl(b1∑)生成的影响。发现对于一定的He流量,Cl2流量对NCl(a1Δ 和NCl(b1∑)生成的影响存在一最佳范围,而最佳He/Cl2配比不是一定值,而是随He流量升高而变大,在实验所考察的He流量范围(5~40 L/min)内,最佳He/Cl
2配比在30∶1~100∶1之间。 相似文献
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Seema Sharma 《Pramana》2007,69(6):1069-1074
The performance of the CMS hadron calorimeter is studied using test beam facilities at CERN. Two wedges of brass-scintillator
calorimeter are exposed to negative and positive beams with momenta between 3 and 300 GeV/c. Light produced in the scintillators
are collected using wavelength shifting fibres and read out using hybrid photodiodes. Each of the wedges has 17 layers of
scintillators. In one of these wedges signal from all 17 layers are grouped together while in the other each layer is read
out separately. The response, energy resolution, longitudinal and lateral shower profiles are measured.
on behalf of the CMS Collaboration 相似文献