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在研制用于对厚的生物样品进行光学断层成像的共焦扫描荧光显微镜时,由于成像信号十分微弱及存在很强的多次散射作用,因此杂散光的抑制非常重要,而信噪比、信号背景比就成为决定能否获得高对比度、高分率图像的关键。运用光学信息量的概念,在已有的光学成像系统信息量计算、共焦扫描荧光显微镜信噪比及传递函数计算的基础上,详细分析了共焦扫描荧光显微镜信息量与信噪比等之间的定量关系。该关系表明,为了充分利用共焦扫描荧光显微镜的成像性能,必须选择适当的探测小孔。所得的结果对于共焦扫描荧光显微成像系统的研制有重要的实用价值。 相似文献
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本文提出了一种基于消球差复合液芯柱透镜快速、准确测量液体折射率的新方法——液芯柱透镜散焦宽度法.该方法利用消球差复合液芯柱透镜在较宽折射率范围内系统球差小、成像准确的特点,基于不同折射率在成像系统上呈现一一对应的散焦图像,仅需采集一幅散焦图像即可得到待测液体的折射率.用该方法测量了室温(20℃)下21组不同液体的折射率,测量结果与用阿贝折射仪测量结果一致,用ZEMAX和光线追迹逐面成像法仿真的散焦宽度图像与实验图像一致.用该方法测量液体折射率具有系统简单、稳定性好、操作简便、测量速度快等特点. 相似文献
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《光学学报》2015,(5)
报道了一套具有活体光学断层成像能力的全场相干层析系统(FF-OCT)。该系统基于Linnik白光干涉显微结构,使用非相干光卤钨灯照明,参考臂与样品臂采用完全相同数值孔径的显微物镜成像,实验测得的轴向分辨率为1.3μm,横向分辨率为0.89μm,640 pixel×480 pixel的CCD采集干涉信号得到的成像深度为80μm。描述了基于单片机控制的相位调制方式,采用该方法可提高成像速度(从60 s/frame提高到1 s/frame断层图)和图像信噪比(SNR),并用所获得的洋葱表皮细胞的断层图(SNR从18.36 d B提高到23.30 d B)和三维图像验证其有效性。探究了由于大数值孔径显微物镜和折射率不匹配产生球差的原因并给出补偿方法,实验结果表明,补偿后的断层图像呈现了更多的细节(SNR从25.41 d B提高到29.54 d B)。利用该系统还实现了人体手指皮肤在体细胞水平的细微结构断层成像。对人体肝组织进行成像表明,所研制的FF-OCT系统有分辨正常组织与肝癌组织的能力,从而证明了研制的全场光学相干层析系统在癌症诊断领域的价值。该系统的研制为取代冰冻切片检测的快速辅助诊断手段奠定基础。 相似文献
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为实现三维光存储中折射率失配引起的球差补偿,建立了光学存储系统模型,获得了折射率失配引起的波前偏差函数与存储深度的表达式.采用泽尔尼克循环多项式对波前偏差函数进行补偿展开.在双光子荧光和单光子共焦荧光读出方式下,均可获得读出荧光强度与存储深度的关系:在折射率失配引起的球差未得到补偿矫正的情况下,存储深度在200 μm左右读出荧光强度基本上下降为零;当折射率失配引起的初级球差被补偿矫正后,读出荧光强度随存储深度的下降得到较好改善;当折射率失配引起的二级球差被补偿矫正后,存储深度在1 mm内存储点强度随深度基本上没有明显地变化.并且对像差补偿方法进行了具体地分析. 相似文献
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为实现三维光存储中折射率失配引起的球差补偿,建立了光学存储系统模型,获得了折射率失配引起的波前偏差函数与存储深度的表达式.采用泽尔尼克循环多项式对波前偏差函数进行补偿展开.在双光子荧光和单光子共焦荧光读出方式下,均可获得读出荧光强度与存储深度的关系:在折射率失配引起的球差未得到补偿矫正的情况下,存储深度在200μm左右读出荧光强度基本上下降为零;当折射率失配引起的初级球差被补偿矫正后,读出荧光强度随存储深度的下降得到较好改善;当折射率失配引起的二级球差被补偿矫正后,存储深度在1mm内存储点强度随深度基本上没有明显地变化.并且对像差补偿方法进行了具体地分析. 相似文献
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The effects of on-axis spherical aberration and defocus on focusing across a spherical interface between two materials of mismatched refractive index are discussed. A vectorial integral representation for high aperture focusing in this configuration is formulated and an analytical expression for the spherical aberration function is derived. Numerical simulations are performed to analyse the effects of the spherical interface on both the transverse and axial intensity profiles. The results from these numerical simulations are important industrially in understanding the resolution enhancements from solid immersion lens technology, as well as being of more fundamental interest in calculating the distribution at the focal plane under different solid immersion lens configurations. 相似文献
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结合衍射理论和矩阵光学方法得出抛物面型X射线组合折射透镜的光学性能指标(包括其焦距的严格表达式、薄透镜近似的判定准则、透过率和有效孔径,以及极限聚焦光斑尺寸等).采用X射线深度光刻技术实际制作了PMMA材料抛物面型X射线组合折射透镜并给出了工艺测试结果.最后在北京同步辐射装置(BSRF)上,实际构建了基于3种不同结构参数的PMMA材料抛物面型X射线组合折射透镜的微束聚焦实验系统.并实际测试了其聚焦性能,均获得了良好的聚焦效果,给出实测结果并对实测结果进行了分析和讨论. 相似文献
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高斯光束经过负球差透镜的聚焦 总被引:2,自引:0,他引:2
本文讨论高斯光束经过负球差透镜的聚焦,得到了聚焦光场轴上点的光强分布的表示式,并对其进行数值计算。数值计算结果表明,在负球差的情况下,得到光强的最大点位置(最佳聚焦点)相对于无球差情况,往透镜方向移动,并且,最佳聚焦点的光强较无球差时大,当Nw=1,Na=5,kS1=-0.2时,得到的最佳聚焦点的光强是无球差时的1.34倍。本文还讨论了透镜的菲涅尔数对聚焦光场分布的影响。结果表明,当透镜的菲涅尔数小于1时,球差对高斯光束的聚焦的影响可以忽略。 相似文献
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Direct optical fabrication of 3D photonic crystals in a high refractive index LiNbO3 crystal by using the femtosecond laser-induced microexplosion method is investigated. The focal distortion, caused by the refractive index mismatch-induced spherical aberration, can be significantly reduced by using a so-called threshold fabrication method. As a result, 3D fcc photonic crystals are fabricated by stacking quasi-spherical voids layer by layer. Photonic stopgaps with suppression rates of up to 30% in the transmission spectra are observed. The angle dependence of the stopgaps is also revealed. 相似文献
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Li Kai Patrizio Massoli Antonio D'Alessio 《Particle & Particle Systems Characterization》1994,11(5):385-390
The finely stratified sphere model was used to calculate scattered electromagnetic fields from radially inhomogeneous spherical particles illuminated by electromagnetic plane waves. The calculation results show that radial gradients of the real part of the refractive indices change the ray paths into curved lines inside large spherical particles, resulting in fluctuations of rainbow positions for droplets during heat transfer processes. The light intensity in the forward scattering region is found to be useful to infer information about the profile of the imaginary part of the refractive index. 相似文献
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The phase singularities of focused dark-hollow Gaussian beams in the presence of spherical aberration are studied. It is shown that the evolution behavior of phase singularities of focused dark-hollow Gaussian beams in the focal region depends not only on the truncation parameter and beam order, but also on the spherical aberration. The spherical aberration leads to an asymmetric spatial distribution of singularities outside the focal plane and to a shift of singularities near the focal plane. The reorganization process of singularities and spatial distribution of singularities are additionally dependent on the sign of the spherical aberration. The results are illustrated by numerical examples. 相似文献
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采用量子模型对近共振激光驻波原子透镜会聚Cr原子束、形成纳米量级光栅结构的物理过程进行数值模拟。为提高原子透镜的成像质量,对各种像差,如衍射像差、球差、色差、及原子束发散角、原子磁支能级、原子同位素等因素引起的像差进行了理论分析。模拟结果表明,相比粒子光学模型,量子模型能更加精确地描述原子会聚结果,且能解释原子在驻波光场中的衍射现象。在各种像差中,原子束发散角是最主要的因素,其影响大于衍射像差、球差、色差。原子的磁支能级、同位素等因素对像差影响很小,可以忽略不计。激光冷却准直原子束的方法可以减小束发散角引起的像差,压缩原子速度Vz分布范围的方法可以减小色差。 相似文献
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部分相干光经柱面球差透镜聚焦所产生的焦移 总被引:7,自引:7,他引:0
利用Collins公式得出光强均匀部分相干光经柱面球差透镜聚焦后的轴上光强分布,并通过数值模拟的方法研究了入射光的菲涅耳数、相干度和透镜的球差对轴上点光强分布的影响.结果显示,当菲涅耳数较小、空间相干度较小的部分相干光经无球差透镜聚焦时,轴上点光强分布会产生焦移现象,而当部分相干光被球差透镜聚焦时,也会有焦移现象产生. 相似文献
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V. Yu. Osipov 《Technical Physics》1998,43(9):1075-1082
Focusing of a high-power laser beam, whose initial wave front is deformed by spherical aberration and astigmatism, in a medium
with refractive-index nonlinearity is investigated by the computer experiment method. It was found that the extended formations
which arise near the focus are no longer diffraction catastrophes, since they are structurally unstable. It is shown that
weak disturbances of the shape of the initial wave front produce extremely strong distortions of the optical field in the
focusing region. As the wave propagates in the z direction, spatial chaos in the distribution of the optical field develops in the region of focusing (from 137 to 142 mm).
Optical turbulence arises in the focusing region as a result of self-diffraction of light by self-induced nonuniformities
of the refractive index of the medium. After the region with the smallest cross section of the formation near the focus, the
three-dimensional optical field has the form of chaotically dispersing “splashes” and extended “filamentary ejecta.”
Zh. Tekh. Fiz. 68, 74–83 (September 1998) 相似文献