The authors have no acknowledgements.

1.测量的前期准备注意:用于实验的样品是MEMS电极。金电极被制作用剥离工艺在硅晶片上。样品是18毫米×18毫米晶圆与周期性结构（电极）用1mM周期<ol><li>登录到日志使用该系统之前。 </li><li>打开电脑，激光和翻译级功率。 </li><li>放置在MEMS电极/微膜片样品。 <ol><li>放置在MEMS样品中使用镊子将样本保持器的中间。 </li><li>调整样品架，以在光束路径中的电极的位置。的视图的最大测量场由相机传感器尺寸限定。它是为2.3mm×1.8 mm的矩形。 </li></ol></li><li>使用垂直方向机动阶段，移动系统近似1.5厘米远离样品。 </li></ol> 2.软件设置调整<ol><li>打开手机沃导航软件。手机沃导航是我们的C ++开发的内部程序。 </li><li>点击成像源按钮选择实验适当的相机。选择黑白CCD摄像机。避免彩色照相机在此设置中，因为使用了单色二极管激光器。此外，对于相同数量的像素，分辨率将使用彩色摄像机时更低。 <ol><li>在设备设置选项卡，选择Y800（1280×960）视频格式和每秒的视频速率15帧。 </li></ol></li><li>点击黄色的播放按钮来启动相机。与印条纹（全息图）对象的图像应该会出现。 <ol><li>调整优化增益和曝光参数，如果需要的话，以避免图像的饱和度。 </li></ol></li><li>使用实时视频窗口摄影机视图，调整样品位置精确选择区域，调查的样本。 </li><li>打开设置选项卡。 <ol><li>在配置选项卡，选择表面的类型（反射或透明）LA的，波长相机的丝氨酸，和像素大小。激光是二极管激光在633nm工作。摄像机的像素尺寸是4,650纳米。样品是如此反射模式应该选择镜面的MEMS电极装置。 注:CDHM配置允许被测定仅反射面。然而，该软件还可以用于当不同的数字全息系统被用于13来测量透明样品。在此设置的变化改变从相位高度计算公式。的确，光程差计算为透明的样品稍有不同，因为它包括对象折射率。 </li><li>选择卷积重建算法和设置重建距离为零。选择的1或2个重建步骤。 注意:重​​建距离参数可以稍后通过考虑从全息图得到的强度图像和使用自动聚焦来限定。重建步骤定义的数目用于实现菲涅耳积分和模拟波束传播步骤。第一种方法计算积分一次作为单个傅立叶变换。将2步将评估两倍积分。这增加了更多的灵活性，在网格间距，但在计算上是低效率的20。 </li><li>在后处理选项卡，选择所需的展开算法得到最终解开形象。选择质量映射算法。 注:在软件中，Goldstein和质量之间的选择映射算法可以进行。后来呈现出强劲，快速的空间相位展开。质量映射算法是基于引导相如21所述的展开。 </li></ol></li></ol> 3.数据采集<ol><li>按傅立叶变换图标打开傅立叶频谱窗口。其中0级和两个+ 1，-1订单应该会出现。如果不是这种情况，检查样品是在合适的位置，并调整抢占d再次曝光时间。 </li><li>停止实时测量模式。通过使用过滤器工具选择衍射级（正或负频率）中的一个。所选择的区域应当足够大，使得所需要的相位恢复的所有频率都存在。再次打开实时模式。 注意:负顺序的选择将只影响的相位的符号中的最后的结果， 也就是，最后的 3D图像将被反转。 </li><li>打开阶段窗口。检查未启用的展开模式。与包裹条纹印对象的灰色相位图像应该出现。 </li><li>利用电动垂直阶段，以减少相图像中的条纹的数目。当只有1或2条纹留在图像上，停止机动阶段。 注意:该系统是基于干涉。因此，它是对振动敏感。移动z方向机动阶段之后，用户应该等待1或2秒的包裹相位图像出现agai前ñ。同样重要的是在测量过程中，以避免振动，以得到稳定的相位图像。 </li><li>点击自动对焦按钮22找到最好的重建距离。一个可能需要使用自动对焦多次，直至强度图像显示锐利和清晰的接近最佳重建距离。如在22中所述的自动聚焦是基于一个高效和时间有效的角谱方法。 注意:聚焦滑动条可用于微调。然后，点击中央对焦按钮来记录当前重建的距离。有时看起来最重点不是具有自动对焦选项中。在这种情况下，手动输入重建距离找到最好的聚焦。 </li><li>启用展开的模式，通过点击去包裹按钮查看展开的相位图像。 </li></ol> 4，数据可视化和分析测量静<ol><li>打开3D图像窗口中看到最终的3D样品的图像。使用可用的选项，观察最终的结果（旋转，彩色地图，刻度显示...）。 </li><li>单击平铺窗口按钮安排窗口在不重叠，并显示所有的测量窗口。 </li><li>使用线标尺上绘制的展开相位图像上感兴趣的区域的线。在线路图形窗口中，感兴趣的区域的横截面剖面图，可以观察到。使用两个绿色线标记物，以提取对象（ 图5）的近似高度。 表面粗糙度也可以在样品的平坦的顶部得到的。 </li><li>保存.JPEG格式，最后阶段的形象，如果需要将其导入到其他软件。 </li></ol> 5.样品制备和数据分析的动态测量<ol><li>放置在一个供热站板微隔膜。样品将不从板直到实验结束被移除。 </li><li>记录的MICR的全息图Ó膜片在由以下第2和3将用作变形分析的参考上述过程环境温度。 </li><li>保存在计算机上的相位数据。 </li><li>打开实验室加热板。 </li><li>利用温度旋钮，变化在50℃的步骤，从50℃至300℃的温度。对于每个温度步，保存.jpeg格式的相位图图像。 </li><li>减去从记录获取变形数据的其他相位图的初始环境温度的相位图。 注:该后处理工序可以用简单的MATLAB代码来实现。所得到的不同阶段被装入MATLAB和执行简单的矩阵减法。然后将不同的变形阶段的横截面图可以得到。 </li></ol>

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The authors have nothing to disclose.

在这次审查中，我们提供了一个协议，通过紧凑的系统依靠数字全息精确地恢复不同的MEMS器件的定量形态。在静态和动态模式的MEMS表征证明。获得微通道的MEMS的定量3D数据。为了验证该系统的准确度，结果已在CDHM和原子力显微镜进行比较。良好的协议发现意味着数字全息可以是三维成像的可靠技术。结果表明，该系统能够10纳米的深度分辨率。此外，在微通道中获得的结果表明，该系统可在MEMS?...

微纳米物体的计量是为行业和研究人员具有重要意义。事实上，对象的小型化代表了光学测量了新的挑战。微机电系统（MEMS）通常定义了微型机电系统，并且通常包括组件，例如微传感器，微致动器，微电子和微结构。它已经发现，在不同的领域，如生物技术，医药，通信和传感1多种应用。近日，日益复杂以及测试对象的逐步小型化功能要求的适合表征技术的MEMS的发展。高通量制造这些复杂微系统的需要的先进在线测量技术的实施，量化特征参数和所造成的工艺条件2有关的缺陷。例如，几何参数的偏差在MEMS器件ETERS影响系统性能，并具有待表征。此外，行业需要高分辨率测量性能，如全三维（3D）测量，看，高成像分辨率的大场，并实时分析。因此，有必要保证可靠的质量控制和检验过程。此外，它需要测量系统是在生产线上容易地实现的，从而相对紧凑要在现有的基础设施安装。 全息，这是首次由的Gabor 3引入，是一种技术，它允许一个对象的全量化信息恢复通过记录一个参考和一个目的波到感光介质之间的干涉。在此过程中被称为记录，一个场的振幅，相位和偏振被存储在介质中。那么对象波场可以通过参考光束发送到我的恢复dium，被称为全息图的光学读取的处理。由于传统的探测器只记录了波的强度，全息一直很感兴趣的话题在过去五十年，因为它可以访问更多的信息的电场。然而，传统的全息几个方面让它不切实际的行业应用。实际上，感光材料是昂贵的并且在记录过程通常需要高度的稳定性。在高清晰度摄像机传感器的改进，如电荷耦合器件（CCD）已经开通的数字计量的新方法。其中的一个技术被称为数字全息4。在数字全息（DH）时，全息图记录在照相机（记录介质）上和数值的过程被用于重建的相位和强度信息。该记录和重建中所示连接 :与常规全息，可以经过两个主要方法获得的结果古尔1。然而，如果记录是类似于常规全息，重建是唯一的数值5。数值重建过程示于图2中 。两个程序都参与了重建过程。首先，对象波场从所述全息图检索。全息图被乘以一数值基准波得到在全息图平面的物体波前。其次，复合对象的波阵面进行了数值传播到图像平面。在我们的系统中，采用卷积方法6进行此步骤。得到的重建场是一个复杂的函数，因而相位和强度可以被提取提供感兴趣对象上的定量高度信息。全场信息存储在全息方法的能力，并利用计算机技术进行快速的数据处理提供了实验配置更多的灵活性和显著增加SPEE实验过程的研发，开辟新的可能性，开发署作为MEMS和微系统7,8动态计量工具。 相衬成像的数字全息现在是公认的和十几年前9首次提出。事实上，通过组合数字全息和显微镜显微设备的调查已经在许多研究10，11，12，13进行。基于高相干性14和低相干15源17的几个系统，以及不同类型的几何13,16的， （线，偏轴，公共路径...）已提交。另外，在线路数字全息先前已经在MEMS器件18，19的表征使用。然而，这些系统通常是难以实现和笨重，使得它们不适合于工业应用。在这项研究中，我们提出了一种基于AXI关闭一个紧凑的，简单的和镜头自由制度s的数字全息能够为实时MEMS检测和表征。紧凑型数字全息显微镜（CDHM）是一个镜头少数字全息系统研发并获得专利，获得微镜面尺寸物体的三维形态。在我们的系统中，一个10毫瓦，高度稳定的，温度控制的二极管激光器在638纳米工作耦合到一个单模式光纤。正如图3所示，从光纤发出的发散光束被分成由一个光束分离器的基准和一个物体光束。参考光束路径包括一个倾斜的反射镜来实现离轴几何形状。物体光束被散射和被样品反射。两个光束干涉CCD上给予全息图。印到图像的干涉图案被称为空间载波并允许定量相位信息，只有一个图像的恢复。数值重建是使用一个共同的傅立叶变换和卷积算法作为站进行特德以前。镜头的更少的配置具有几个优点使它吸引力。由于没有透镜使用时，输入光束是发散波提供自然几何放大，从而提高了系统的分辨率。此外，它是自由在典型的光学系统中所遇到的像差。如可以在图3B中可以看到，该系统可以做得紧凑（55x75x125毫米3），轻量（400克），并且因此可以容易地集成到工业生产线。

<table><tbody><tr><td>2 MP Camera</td><td>Imaging Source</td><td>DMX 41BU02</td><td>used to record the hologram. 4.65&amp;nbsp;microns pixel size</td></tr><tr><td>Motorized X,Y,Z Translation Stage</td><td>Zaber Technology&amp;nbsp;</td><td>TLS28-M</td><td>Holder for the system&amp;nbsp;</td></tr><tr><td>Beam splitter</td><td>Edmund optics</td><td>49-003</td><td>Cube Beam splitter. Separate and recombine the object and reference beam</td></tr><tr><td>Laser&amp;nbsp;</td><td>Micro Laser Systems, Inc.</td><td>SRT-F635S-20/OSYS</td><td>Diode laser</td></tr><tr><td>Mirror</td><td>Edmund Optics</td><td>#43-412-566</td><td>1&quot; Dia. Protected Gold, &amp;lambda;/20 Flat Zerodur</td></tr><tr><td>monomode Fiber</td><td>Thorlabs</td><td>S405-XP</td><td>Single Mode Optical Fiber, 400 - 680 nm, &amp;Oslash; 125 &amp;micro;m Cladding</td></tr><tr><td>Sample holder</td><td>Edmund Optics</td><td>#39-930</td><td>Ideal Positioning Platform, &amp;plusmn;35&amp;nbsp;mm Travel in Both X and Y</td></tr><tr><td>Hotplate</td><td>Thermolyne Mirak hotplate</td><td>Barnstead International HP72935-60</td><td>temperature range 40-370 &amp;deg;C</td></tr><tr><td>Holoscope Software</td><td>d&#039;Optron Pte Ltd</td><td></td><td>software developed by the NTU researchers&amp;nbsp;</td></tr></tbody></table>

compact lens-less digital holographic microscope for mems inspection and characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

上述协议被设计来检查和表征使用CDHM系统MEMS和微型设备。在我们的系统中，单模式光纤耦合到二极管激光器在633纳米波长下操作。由于发散光束的配置，它向物体光束和参照光束路径匹配，以获得可被重构的全息图是很重要的。这是通过样品的相对于该系统小心垂直定位来实现的。在计算出的包裹相位图像，条纹的数目是通过改变系统高度位置降低到最低限度。它确保?...

Watch this Scientific Journal Video about Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization at JoVE.com

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

我们提出了一个小巧的反射全息数字化系统（CDHM）MEMS器件的检测和鉴定。论证采用发散输入波提供自然几何放大倍率的镜头，无设计。静态和动态的研究介绍。

紧凑的镜头少数字全息显微镜的MEMS检测与表征

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...

compact-lens-less-digital-holographic-microscope-for-mems-inspection

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

10.2K 次观看.  Nanyang Technological University. 我们提出了一个小巧的反射全息数字化系统（CDHM）MEMS器件的检测和鉴定。论证采用发散输入波提供自然几何放大倍率的镜头，无设计。静态和动态的研究介绍。 

视频: Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

Lensless Fluorescent Microscopy on a Chip

On-chip lensless imaging in general aims to replace bulky lens-based optical microscopes with simpler and more compact designs, especially for high-throughput screening applications. This emerging technology platform has the potential to eliminate the need for bulky and/or costly optical components through the help of novel theories and digital reconstruction algorithms. Along the same lines, here we demonstrate an on-chip fluorescent microscopy modality that can achieve e.g., &lt;4&mu;m spatial resolution over an ultra-wide field-of-view (FOV) of &gt;0.6-8 cm2 without the use of any lenses, mechanical-scanning or thin-film based interference filters. In this technique, fluorescent excitation is achieved through a prism or hemispherical-glass interface illuminated by an incoherent source. After interacting with the entire object volume, this excitation light is rejected by total-internal-reflection (TIR) process that is occurring at the bottom of the sample micro-fluidic chip. The fluorescent emission from the excited objects is then collected by a fiber-optic faceplate or a taper and is delivered to an optoelectronic sensor array such as a charge-coupled-device (CCD). By using a compressive-sampling based decoding algorithm, the acquired lensfree raw fluorescent images of the sample can be rapidly processed to yield e.g., &lt;4&mu;m resolution over an FOV of &gt;0.6-8 cm2. Moreover, vertically stacked micro-channels that are separated by e.g., 50-100 &mu;m can also be successfully imaged using the same lensfree on-chip microscopy platform, which further increases the overall throughput of this modality. This compact on-chip fluorescent imaging platform, with a rapid compressive decoder behind it, could be rather valuable for high-throughput cytometry, rare-cell research and microarray-analysis.

A lensless on-chip fluorescent microscopy platform is demonstrated that can image fluorescent objects over an ultra-wide field-of-view of e.g., &#62;0.6-8 cm2 with &#60;4&#956;m resolution using a compressive sampling based decoding algorithm. Such a compact and wide-field fluorescent on-chip imaging modality could be valuable for high-throughput cytometry, rare-cell research and microarray-analysis.

片上的无透镜荧光显微镜

On-chip lensless imaging in general aims to replace bulky lens-based optical microscopes with simpler and more compact designs, especially for ...

科研

生物工程

Lensfree On-chip Tomographic Microscopy Employing Multi-angle Illumination and Pixel Super-resolution

Tomographic imaging has been a widely used tool in medicine as it can provide three-dimensional (3D) structural information regarding objects of different size scales. In micrometer and millimeter scales, optical microscopy modalities find increasing use owing to the non-ionizing nature of visible light, and the availability of a rich set of illumination sources (such as lasers and light-emitting-diodes) and detection elements (such as large format CCD and CMOS detector-arrays). Among the recently developed optical tomographic microscopy modalities, one can include optical coherence tomography, optical diffraction tomography, optical projection tomography and light-sheet microscopy. 1-6 These platforms provide sectional imaging of cells, microorganisms and model animals such as C. elegans, zebrafish and mouse embryos.
Existing 3D optical imagers generally have relatively bulky and complex architectures, limiting the availability of these equipments to advanced laboratories, and impeding their integration with lab-on-a-chip platforms and microfluidic chips. To provide an alternative tomographic microscope, we recently developed lensfree optical tomography (LOT) as a high-throughput, compact and cost-effective optical tomography modality. 7 LOT discards the use of lenses and bulky optical components, and instead relies on multi-angle illumination and digital computation to achieve depth-resolved imaging of micro-objects over a large imaging volume. LOT can image biological specimen at a spatial resolution of &lt;1 &mu;m x &lt;1 &mu;m x &lt;3 &mu;m in the x, y and z dimensions, respectively, over a large imaging volume of 15-100 mm3, and can be particularly useful for lab-on-a-chip platforms.

Lensfree optical tomography is a three-dimensional microscopy technique that offers a spatial resolution of &lt;1 &mu;m &times; &lt;1 &mu;m &times; &lt;3 &mu;m in x, y and z dimensions, respectively, over a large imaging-volume of 15-100 mm3, which can be particularly useful for integration with lab-on-a-chip platforms.

lensfree芯片断层用人多角度的光照和像素超高分辨率的显微镜

Tomographic imaging has been a widely used tool in medicine as it can provide three-dimensional (3D) structural information regarding objects of different ...

Demonstration of a Hyperlens-integrated Microscope and Super-resolution Imaging

The use of super-resolution imaging to overcome the diffraction limit of conventional microscopy has attracted the interest of researchers in biology and nanotechnology. Although near-field scanning microscopy and superlenses have improved the resolution in the near-field region, far-field imaging in real-time remains a significant challenge. Recently, the hyperlens, which magnifies and converts evanescent waves into propagating waves, has emerged as a novel approach to far-field imaging. Here, we report the fabrication of a spherical hyperlens composed of alternating silver (Ag) and titanium oxide (TiO2) thin layers. Unlike a conventional cylindrical hyperlens, the spherical hyperlens allows for two-dimensional magnification. Thus, incorporation into conventional microscopy is straightforward. A new optical system integrated with the hyperlens is proposed, allowing for a sub-wavelength image to be obtained in the far-field region in real time. In this study, the fabrication and imaging setup methods are explained in detail. This work also describes the accessibility and possibility of the hyperlens, as well as practical applications of real-time imaging in living cells, which can lead to a revolution in biology and nanotechnology.

The use of a hyperlens has been regarded as a novel super-resolution imaging technique due to its advantages in real-time imaging and its simple implementation with conventional optics. Here, we present a protocol describing the fabrication and imaging applications of a spherical hyperlens.

Hyperlens 综合显微镜和超分辨率成像的演示

The use of super-resolution imaging to overcome the diffraction limit of conventional microscopy has attracted the interest of researchers in biology and ...

工程学

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by local enhancement of electric field intensity that strengthens light-matter interactions, enabling applications such as surface-enhanced Raman scattering (SERS) and surface plasmon enhanced sensing. In the presence of magneto-optically active materials, the local field enhancement gives rise to anomalous magneto-optical activity. Typically, the confined modes of a given photonic crystal depend strongly on the wavelength and incidence angle of the incident electromagnetic radiation. Thus, spectral and angular-resolved measurements are needed to fully identify them as well as to establish their relationship with the magneto-optical activity of the crystal. In this article, we describe how to use a Fourier-plane (back focal plane) microscope to characterize magneto-optically active samples. As a model system, here we use a plasmonic grating built out of magneto-optically active Au/Co/Au multilayer. In the experiments, we apply a magnetic field on the grating in situ and measure its reciprocal space response, obtaining the magneto-optical response of the grating over a range of wavelengths and incident angles. This information enables us to build a complete map of the plasmonic band structure of the grating and the angle and wavelength dependent magneto-optical activity. These two images allow us to pinpoint the effect that the plasmon resonances have on the magneto-optical response of the grating. The relatively small magnitude of magneto-optical effects requires a careful treatment of the acquired optical signals. To this end, an image processing protocol for obtaining magneto-optical response from the acquired raw data is laid out.

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

光子纳米结构的光谱和角度解析磁-光学特性

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by ...

Lensless On-chip Imaging of Cells Provides a New Tool for High-throughput Cell-Biology and Medical Diagnostics

Conventional optical microscopes image cells by use of objective lenses that work together with other lenses and optical components. While quite effective, this classical approach has certain limitations for miniaturization of the imaging platform to make it compatible with the advanced state of the art in microfluidics. In this report, we introduce experimental details of a lensless on-chip imaging concept termed LUCAS (Lensless Ultra-wide field-of-view Cell monitoring Array platform based on Shadow imaging) that does not require any microscope objectives or other bulky optical components to image a heterogeneous cell solution over an ultra-wide field of view that can span as large as ~18 cm2. Moreover, unlike conventional microscopes, LUCAS can image a heterogeneous cell solution of interest over a depth-of-field of ~5 mm without the need for refocusing which corresponds to up to ~9 mL sample volume. This imaging platform records the shadows (i.e., lensless digital holograms) of each cell of interest within its field of view, and automated digital processing of these cell shadows can determine the type, the count and the relative positions of cells within the solution. Because it does not require any bulky optical components or mechanical scanning stages it offers a significantly miniaturized platform that at the same time reduces the cost, which is quite important for especially point of care diagnostic tools. Furthermore, the imaging throughput of this platform is orders of magnitude better than conventional optical microscopes, which could be exceedingly valuable for high-throughput cell-biology experiments.

Lensfree on-chip imaging and characterization of cells is illustrated. This on-chip cell imaging approach provides a compact and cost-effective tool for medical diagnostics and high-throughput cell biology applications, making it especially suitable for resource poor settings.

无透镜片上的细胞成像提供了一种高通量细胞生物学和医疗诊断的新工具

Conventional optical microscopes image cells by use of objective lenses that work together with other lenses and optical components. While quite ...

生物学

Uncovering Hidden Dynamics of Natural Photonic Structures Using Holographic Imaging

In this method, the potential of optics and holography to uncover hidden details of a natural system's dynamical response at the nanoscale is exploited. In the first part, the optical and holographic studies of natural photonic structures are presented as well as conditions for the appearance of the photophoretic effect, namely, the displacement or deformation of a nanostructure due to a light-induced thermal gradient, at the nanoscale. This effect is revealed by real-time digital holographic interferometry monitoring the deformation of scales covering the wings of insects induced by temperature. The link between geometry and nanocorrugation that leads to the emergence of the photophoretic effect is experimentally demonstrated and confirmed. In the second part, it is shown how holography can be potentially used to uncover hidden details in the chemical system with nonlinear dynamics, such as the phase transition phenomenon that occurs in complex oscillatory Briggs-Rauscher (BR) reaction. The presented potential of holography at the nanoscale could open enormous possibilities for controlling and molding the photophoretic effect and pattern formation for various applications such as particle trapping and levitation, including the movement of unburnt hydrocarbons in the atmosphere and separation of different aerosols, decomposition of microplastics and fractionation of particles in general, and assessment of temperature and thermal conductivity of micron-size fuel particles.

The paper is primarily focused on the combined power of optical (linear and nonlinear) and holographic methods used to reveal phenomena at the nanoscale. The results obtained from the biophotonic and oscillatory chemical reactions' studies are given as representative examples, highlighting holography's ability to reveal dynamics at a nanoscale.

使用全息成像揭示自然光子结构的隐藏动力学

In this method, the potential of optics and holography to uncover hidden details of a natural system's dynamical response at the nanoscale is exploited. ...

化学

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in medical diagnostics, and for life detection by robotic missions to other planets and moons of the solar system. Currently, sparse bacterial samples are counted by culture plating or epifluorescence microscopy. Culture plates require long incubation times (days to weeks), and epifluorescence microscopy requires extensive staining and concentration of the sample. Here, we demonstrate how to use off-axis digital holographic microscopy (DHM) to enumerate bacteria in very dilute cultures (100-104 cells/mL). First, the construction of the custom DHM is discussed, along with detailed instructions on building a low-cost instrument. The principles of holography are discussed, and a statistical model is used to estimate how long videos should be to detect cells, based on the optical performance characteristics of the instrument and the concentration of the bacterial solution (Table 2). Video detection of cells at 105, 104, 103, and 100 cells/mL is demonstrated in real time using un-reconstructed holograms. Reconstruction of amplitude and phase images is demonstrated using an open-source software package.

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy DHM

Digital holographic microscopy (DHM) is a volumetric technique that allows imaging samples 50-100X thicker than brightfield microscopy at comparable resolution, with focusing performed post-processing. Here DHM is used for identifying, counting, and tracking microorganisms at very low densities and compared with optical density measurements, plate count, and direct count.

用数字全息显微镜 (DHM) 定量化低浓度微生物

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in ...

Digital Inline Holographic Microscopy (DIHM) of Weakly-scattering Subjects

Weakly-scattering objects, such as small colloidal particles and most biological cells, are frequently encountered in microscopy. Indeed, a range of techniques have been developed to better visualize these phase objects; phase contrast and DIC are among the most popular methods for enhancing contrast. However, recording position and shape in the out-of-imaging-plane direction remains challenging. This report introduces a simple experimental method to accurately determine the location and geometry of objects in three dimensions, using digital inline holographic microscopy (DIHM). Broadly speaking, the accessible sample volume is defined by the camera sensor size in the lateral direction, and the illumination coherence in the axial direction. Typical sample volumes range from 200 &#181;m&#160;x 200 &#181;m&#160;x 200 &#181;m using LED illumination, to 5 mm&#160;x 5 mm&#160;x 5 mm or larger using laser illumination. This illumination light is configured so that plane waves are incident on the sample. Objects in the sample volume then scatter light, which interferes with the unscattered light to form interference patterns perpendicular to the illumination direction. This image (the hologram) contains the depth information required for three-dimensional reconstruction, and can be captured on a standard imaging device such as a CMOS or CCD camera. The Rayleigh-Sommerfeld back propagation method is employed to numerically refocus microscope images, and a simple imaging heuristic based on the Gouy phase anomaly is used to identify scattering objects within the reconstructed volume. This simple but robust method results in an unambiguous, model-free measurement of the location and shape of objects in microscopic samples.

Digital Inline Holographic Microscopy DIHM of Weakly-scattering Subjects

The three-dimensional locations of weakly-scattering objects can be uniquely identified using digital inline holographic microscopy (DIHM), which involves a minor modification to a standard microscope. Our software uses a simple imaging heuristic coupled with Rayleigh-Sommerfeld back-propagation to yield the three-dimensional position and geometry of a microscopic phase object.

的弱散射主题内嵌数字全息显微镜（DIHM）

Weakly-scattering objects, such as small colloidal particles and most biological cells, are frequently encountered in microscopy. Indeed, a range of ...

Evaluation and Manipulation of Neural Activity Using Two-Photon Holographic Microscopy

Recent advances in optical bioimaging and optogenetics have enabled the visualization and manipulation of biological phenomena, including cellular activities, in living animals. In the field of neuroscience, detailed neural activity related to brain functions, such as learning and memory, has now been revealed, and it has become feasible to artificially manipulate this activity to express brain functions. However, the conventional evaluation of neural activity by two-photon Ca2+ imaging has the problem of low temporal resolution. In addition, manipulation of neural activity by conventional optogenetics through the optic fiber can only simultaneously regulate the activity of neurons with the same genetic background, making it difficult to control the activity of individual neurons. To solve this issue, we recently developed a microscope with a high spatiotemporal resolution for biological applications by combining optogenetics with digital holographic technology that can modify femtosecond infrared laser beams. Here, we describe protocols for the visualization, evaluation, and manipulation of neural activity, including the preparation of samples and operation of a two-photon holographic microscope (Figure 1). These protocols provide accurate spatiotemporal information on neural activity, which may be useful for elucidating the pathogenesis of neuropsychiatric disorders that lead to abnormalities in neural activity.

We developed a two-photon holographic microscope that can visualize, assess, and manipulate neural activity using high spatiotemporal resolution, with the aim of elucidating the pathogenesis of neuropsychiatric disorders that are associated with abnormal neural activity.

使用双光子全息显微镜评估和操纵神经活动

Recent advances in optical bioimaging and optogenetics have enabled the visualization and manipulation of biological phenomena, including cellular ...

神经科学

Lens-free Video Microscopy for the Dynamic and Quantitative Analysis of Adherent Cell Culture

Here, we demonstrate that lens-free video microscopy enables us to simultaneously capture the kinetics of thousands of cells directly inside the incubator and that it is possible to monitor and quantify single cells along several cell cycles. We describe the full protocol used to monitor and quantify a HeLa cell culture for 2.7 days. First, cell culture acquisition is performed with a lens-free video microscope, and then the data is analyzed following a four-step process: multi-wavelength holographic reconstruction, cell-tracking, cell segmentation and cell division detection algorithms. As a result, we show that it is possible to gather a dataset featuring more than 10,000 cell cycle tracks and more than 2 x 106 cell morphological measurements.

Lens-free video microscopy enables us to monitor cell cultures directly inside the incubator. Here we describe the full protocol used to acquire and analyze a 2.7 day long acquisition of cultured HeLa cells, leading to a dataset of 2.2 x 106 measurements of individual cell morphology and 10584 cell cycle tracks.

无透镜视频显微术在黏附细胞培养动态定量分析中的研究

Here, we demonstrate that lens-free video microscopy enables us to simultaneously capture the kinetics of thousands of cells directly inside the incubator ...