双光子和多光子共焦显微镜的成像理论

对双光子和多光子共焦扫描显微镜的成像理论作了系统的理论分析,导出了双光子和多光子共焦显微镜成像系统的三维点扩散函数和三维光学传递函数,研究结果表明：双光子共焦显微镜比单光子共焦显微镜具有更高的横向分辨率和纵向分辨率,而多光子共焦扫描显微镜又比双光子共焦扫描显微镜具有更高的空间分辨率. 关键词：     

微分干涉差共焦显微膜层微结构缺陷探测系统

多层膜极紫外光刻掩模"白板"缺陷是制约下一代光刻技术发展的瓶颈之一,为提高对掩模"白板"上的膜层微结构缺陷的分辨能力,提出了一种微分干涉差共焦显微探测系统方案。基于标量衍射理论,计算了系统横向和轴向分辨率。利用MATLAB建模仿真,在数值孔径为0.65、工作波长为405 nm时,分析比较了微分干涉差共焦显微系统、传统显微系统和共焦显微系统的分辨率。结果表明微分干涉差共焦显微系统具有230 nm的横向分辨率和25 nm轴向台阶高度差的分辨能力(对应划痕等缺陷形式)。此外,仿真和分析了实际应用中探测器尺寸、样品轴向偏移等的影响,模拟分析了膜层微结构缺陷的探测,结果表明本系统可以探测200 nm宽、10 nm高的微结构缺陷,较另外两种系统有更好的探测能力。     

改善共焦系统轴向分辨率的位相型光瞳滤波器

利用约束全局优化算法———CGO算法,设计了两种用于共焦系统的三区位相型光瞳滤波器.第一种滤波器在不改变系统的横向分辨率的同时,可以大幅度地提高轴向分辨率,提高了系统的层析能力.第二种滤波器在提高系统轴向分辨率的同时,又能提高其横向分辨率,适用于系统的三维成像. 关键词： CGO算法 光瞳滤波器 超分辨     

荧光谱线分布对共焦荧光显微镜分辨率的影响

研究了荧光谱线分布对共焦荧光显微镜中分辨率的影响,导出了荧光谱线分布的荧光功率传输函数、三维脉冲响应函数.数值计算了荧光谱线均匀分布的情况,结果表明：与采用单一中心荧光波长的分辨率比较,共焦荧光显微镜的横向分辨率、纵向分辨率随着荧光谱线范围和色散的增大而下降;谱线响应范围小的探测器有利于分辨率.     

基于数字微镜器件并行共焦成像的光点阵列优化

数字微镜器件(DMD)的灵活性有助于实现并行共焦成像。设计并搭建了基于DMD的并行共焦成像系统,分析了DMD光点阵列对轴向分辨率、横向分辨率和图像对比度的影响,得出了最优光点阵列参数。结果表明:光点越小,则横向和轴向分辨率越高;当光点间距大于光点大小时,增大光点间距对成像的横向分辨率无明显改善;对于1×1微镜,光点间距为光点大小的4倍时对应的图像对比度最高,即1×1光点大小、4倍光点间距为最优光点阵列。对数值孔径为0.25的物镜而言,最优光点阵列对应的横向分辨率优于512lp/mm,轴向分辨率可达7.82μm,均达到衍射极限。基于最优光点阵列的三维体光栅成像比宽场成像具有更高的分辨率和明显的层切效果,与激光扫描共焦成像相比无较大差距。基于DMD的并行共焦成像系统在保证高速成像的前提下,实现了高分辨率和高图像对比度的光学层切成像,在实时成像和三维成像中有一定的优势和应用前景。     

激光共焦扫描显微镜的分辨率及像差补偿

从激光共焦扫描显微镜的基本原理出发,深入讨论激光共焦扫描显微镜的深度分辨率和横向分辨率,同时研究三维成像的像差补偿问题。     

反射式光纤共焦扫描成像的研究

建立了反射式光纤共焦扫描成像系统,分析了光纤－集光透镜参数Ａ及物透镜有效数值孔径等对系统成像分辨率的影响。并在此基础上选择了合适参数的透镜,获得了优化的反射式光纤共焦扫描成像系统,测试结果表明,该系统具有亚微米级横向成像能力,微米级向层析能力,成像稳定性那,它将应用于材料及生物组织三维成像检测中。     

具有高空间分辨力的整形环形光式差动共焦测量法

提出一种新的具有高空间分辨力的整形环形光式差动共焦测量方法。该方法通过整形环形光式共焦测量法和锐化爱里斑主瓣，改善系统横向分辨力；通过差动共焦测量法改善系统的轴向分辨力，最终达到提高系统空间分辨能力的目的。理论分析和实验表明：整形环形光内孔归一化半径ε越大，横向分辨力改善越明显，量程扩展范围越宽；当入射光波长λ=632.8nm，物镜数值孔径取NA=0.85，ε=0.5时，该系统的横向分辨力优于0.2μm，轴向分辨力优于2nm。该方法为光触针测量系统空间分辨力的提高提供了1种新的方法，可广泛应用于超精密三维微细结构工件的超精密测量。     

用于高数值孔径物镜的可调光瞳滤波器

根据矢量衍射理论，提出了一种用于提高高数值孔径显微物镜纵向分辨率的可调二元环形光瞳滤波器，通过改变滤波器的环半径获得不同的纵向分辨率，并利用共焦显微术点扩散函数的乘积性大大地降低了旁瓣相对主瓣的比值。模拟结果表明，这种新型滤波器不仅可以提高高数值孔径物镜的纵向分辨率，同时基本上不影响横向分辨率。     

高斯光束共焦扫描激光显微镜的光学传递函数

考虑光源和探测器有一定大小，并引入光源的高斯分布函数，求出此接近实际的共焦扫描成像系统的光学传递函数(OTF)；运用计算机进行数值模拟并讨论光源针孔和探测针孔的大小对横向、纵向分辨率的影响.所得结果在不影响共焦扫描成像系统三维(3D)成像能力的基础上，可以有效地提高系统的信噪比. 关键词：     

Effect of an annular pupil filter on differential confocal microscopy

Combining differential confocal microscopy and an annular pupil filter, we obtained the normalized axial intensity distribution curve of an optical system. We used the sharp slopes of the axial response curve of the optical system to measure the surface profile of a reflection grating. Experimental results prove that this method can extend the axial dynamic range and improve the transverse resolution of three-dimensional profilometry by sacrificing axial resolution.     

Microscopic structured light 3D profilometry: Binary defocusing technique vs. sinusoidal fringe projection

This paper compares the binary defocusing technique with conventional sinusoidal fringe projection under two different 3D microscopic profilometry systems: (1) both camera and projector use telecentric lenses and (2) only camera uses a telecentric lens. Our simulation and experiments found that the binary defocusing technique is superior to the traditional sinusoidal fringe projection method by improving the measurement resolution approximately 19%. Finally, by taking the speed advantage of the binary defocusing technique, we presented a high-speed (500 Hz) and high-resolution (1600×1200) 3D microscopic profilometry system that could reach kHz.     

飞秒激光在三维微细体系中的应用

飞秒激光的超快特性使其能以极低的脉冲能量获得超强光场,并且激光加照区淀积的能量能以通过热扩散途径逸出辐照区域,其与透明物质相互作用是通过双光子或多光子吸收过程实现,故作用区限域于焦点核心很小体积内,因而在三维微制备及生物医学领域有着独到优势。文章介绍了飞秒激光应用于微爆炸、高密度三维光学数据存储、直写光波导及三维光子晶体制备、生物医学工程等方面的最新进展。飞秒激光三维微制备技术在微电子、计算机、光通信、生物医学等高技术领域有着广阔的应用前景。     

Three-dimensional optical transfer of rotating beams

Systems in which the point spread function (PSF) is a rotating beam have increasing use in three-dimensional (3D) microscopy and depth estimation. We analyze in several ways the 3D optical transfer function (OTF) of Gauss Laguerre modes and rotating beams. This is based on analysis of 3D OTFs of general aperture functions. Consequently, we suggest a criterion for depth resolution based on an effective cutoff of the axial frequency response. This criterion can be used to optimize PSFs explicitly and directly, to maximize axial resolution.     

相位测量轮廓术中三维坐标校准新方法

提出了一种新的用于相位测量轮廓术中的三维坐标校准方法。该方法用一个含有三个虚拟校准平面的标准块代替传统相位测量轮廓术校准方法中使用的标准平面，每个虚拟校准平面由多个高度相同但空间离散分布的子区域组成，相应的连续相位恢复是通过一个迭代过程实现的，同时各个子区域还被用于横向坐标的校准。由于各个虚拟校准平面间高度是垂直变化的，传统的相位展开不能得到正确的相对位置关系，基于等效波长概念，提出了一种准确的虚拟校准平面连续相位间相对位置恢复的办法。此校准方法的特点是：在校准过程中不需要标准平面的多次精确平移；仅需要一次测量就可以完成高度和横向坐标的同时校准。文中给出的实验结果说明了该校准方法的有效性和可行性。     

基于共焦原理的反射式自聚焦光纤传感技术研究

基于共焦显微成象原理,提出了一种由自聚焦透镜和X型光纤组成的高精度反射式自聚焦光纤传感器.该传感器具有绝对位置跟踪的特殊能力,并有体积小、抗干扰性强、轴向分辨率高等特点.由实验分析得,其轴向分辨率可达30nm.可用于表面微观形貌、外形尺寸、曲面轮廓等测量领域.     

Profilometry of three-dimensional discontinuous solids by combining two-steps temporal phase unwrapping,co-phased profilometry and phase-shifting interferometry

In this work we review and combine two techniques that have been recently published for three-dimensional (3D) fringe projection profilometry and phase unwrapping, namely: co-phased profilometry and 2-steps temporal phase-unwrapping. By combining these two methods we get a more accurate, higher signal-to-noise 3D profilometer for discontinuous industrial objects. In single-camera single-projector (standard) profilometry, the camera and the projector must form an angle between them. The phase-sensitivity of the profilometer depends on this angle, so it cannot be avoided. This angle produces regions with self-occluding shadows and glare from the solid as viewed from the camera׳s perspective, making impossible the demodulation of the fringe-pattern there. In other words, the phase data is undefined at those shadow regions. As published recently, this limitation can be solved by using several co-phased fringe-projectors and a single camera. These co-phased projectors are positioned at different directions towards the object, and as a consequence most shadows are compensated. In addition to this, most industrial objects are highly discontinuous, which precludes the use of spatial phase-unwrappers. One way to avoid spatial unwrapping is to decrease the phase-sensitivity to a point where the demodulated phase is bounded to one lambda, so the need for phase-unwrapping disappears. By doing this, however, the recovered non-wrapped phase contains too much harmonic distortion and noise. Using our recently proposed two-step temporal phase-unwrapping technique, the high-sensitivity phase is unwrapped using the low-frequency one as initial gross estimation. This two-step unwrapping technique solves the 3D object discontinuities while keeping the accuracy of the high-frequency profilometry data. In scientific research, new art are derived as logical and consistent result of previous efforts in the same direction. Here we present a new 3D-profilometer combining these two recently published methods: co-phased profilometry and two-steps temporal phase-unwrapping. By doing this, we obtain a new and more powerful 3D profilometry technique which overcomes the two main limitations of previous fringe-projection profilometers namely: high phase-sensitivity digitalization of discontinuous objects and solid׳s self-generated shadow minimization. This new 3D profilometer is demonstrated by an experiment digitizing a discontinuous 3D industrial-solid where the advantages of this new profilometer with respect to previous art are clearly shown.     

利用空间坐标变换的三维测量系统

提出了一种新的三维面形测量合成方法，它可以用于大物体及具有复杂而形物体的多次测量，本文将空间坐标变换理论引入到三维面形测量中，并阐述了基于此物相转换方法及图像合成方法。测量结果表明，本方法可以基本消除传统方法中存在的问题，解决了三维测量中的一个瓶颈问题。     

Gerchberg迭代法在三维面形测量中的应用

在基于结构光照明的三维面形测量中,针对有孤立区域物体的条纹图像存在不规则缺陷的问题,提出先对其进行Gerchberg迭代,消除或减少条纹缺陷,获取较完善的迭代条纹,然后再利用傅里叶变换轮廓术(FTP)重建面形。设计了迭代流程,并分析了影响迭代精度的因素,解决了光学加工用具磨盘表面不完善条纹Gerchberg迭代过程中存在的问题,成功地重建了磨盘的三维面形。该工作为表面存在孤立区域的被测物体三维面形测量提供了可供参考的技术方案,也给可实时形变的应力盘三维面形动态测量奠定了基础。     

位错点阵投影的三维数字成像

提出一种基于位错点阵投影的三维数字成像方法。该方法以二维点阵结构光顺序照明参考平面和被测物体表面,通过分析分别投影在参考平面和物体上的点阵的成像过程,建立投射在参考平面和被测物体表面上的点阵中同一点在成像面上横向位置错动与被测物体深度之间的数学模型。依据此模型,通过计算相对应点在成像平面上的横向位移。可计算出物体的深度图像。二维点阵可以在垂直于光轴的平面内做横向和纵向的两维移动,以填补由于离散而丢失的其他空间点的深度信息,获得高空间分辨率。实验验证了该方法的可行性,此方法对于拓扑复杂的表面和大梯度表面有较强的适应性。