该项目是支持的，部分由美国国家科学基金会和空军研究实验室通过接触程序。

1。传感器的设计与制造<ol><li>设计一个与一个或多个集成电路的空腔（或“槽”）的平行板波导。请参阅图1和图2。几何可以基于我们以前的出版物8,9中给出的或专门设计用于特定的应用。总的指导原则的建议： <ol><li>板间隔：在这个实验中的板间距为1mm的用于有效地耦合到TE1模式，而不需要特殊的光学。它还确保单模传播在感兴趣的频率。当使用其他的板间距，多模传播，色散和耦合效率应予以考虑。 </li><li>垫片：这板间距保持绝缘垫片。小片玻璃厚度非常均匀，使优秀的间隔 - 在我们的例子中，我们使用的碎片从一个破碎的显微镜载物片的​​厚度为1 mm + / - 3微米。 </lI&gt; <li>板尺寸：板本身应该足够宽输入光束相比，他们可以被认为是无限的。 （在我们的例子中，为1.2厘米的光束。4.75厘米）每块板的厚度必须是厚得多的趋肤深度，和厚钢板（大于1厘米）的建议，以减少能量的可能性，通过上方或下方的波导并到达检测器。传播长度应该是足够的，该槽至少是两倍自身的远离输入和输出面的宽度，但最小化，以减少色散。 </li><li>底板几何：为了允许容易访问的槽，底部光波导板应明显宽于顶板，而凹槽几乎延伸（但不完全）的板的整个宽度上。 （参见图1），这使得它更容易访问槽和监测水平的灌装。 </li><li>螺丝：顶板和底板有螺丝可以插入一个扩展，使持有的浪潮指导不阻碍的槽或传播路径的情况下一起。在底板上的孔（参见图1）有螺纹，而顶部是不。 </li><li>空腔几何：该槽设计将取决于所希望的谐振频率，所需的线宽，和所选择的板间距，以及其他因素。重要的是要考虑你的制作技术的局限性很窄的或很浅的凹槽。多通道传感的多槽有额外的要求10。 </li><li>未开槽的版本：在每一个方面，不的槽相同的设计，也可制作，被用来作为一个参考。 </li></ol></li><li>的波导管的制备，可以通过机械加工完成。重要提示：不要生硬的边缘的板块，特别是对输入的人脸。圆边是标准的做法，许多机加工车间出于安全原因，但是圆滑的边缘上输入的人脸会扭曲信号。 </li><li>装配程序。已制作的两个极板之后，他们应该被组装成的波导管。 <ol><li>使用的L形支架或其它平面的对象来创建的结构，与两个平坦表面垂直于彼此。放置在底板的水平表面上，然后按它紧靠垂直表面。放置的电介质间隔物作为距离尽可能的螺丝孔（每两个螺钉，每侧各一个），小心不要妨碍槽或延伸超出输入的人脸。 </li><li>小心地将顶板的垂直表面齐平，然后向下滑动坐在底板和隔板。这两个板块的垂直表面平齐，插入螺丝。拧下来以交替模式增量。此过程导致的波导管与一个完全平坦的输入人脸和均匀的板间距。 </li></ol></li></ol> 2。实验装置这个协议假定用户公顷s接入传输几何太赫兹时域光谱仪（在我们的例子中，Picometrix T-射线4000），是获得的时域波形和傅里叶变换到频域的熟悉。 <ol><li>共焦配置。不存在的话，四个透镜应共焦的方向引入的光束路径的路径的中点处，以提供一紧焦点。 </li><li>将光圈的焦点。该孔应足够大，来阻止所有除了通过波导传播的辐射。光圈的大小将决定在波导中传播光束的大小，（在我们的例子中，有12毫米）。 </li><li>地点波导紧接后面的孔，与输入面与孔接触并与波导管传播轴与光轴对齐尽可能密切。这里的取向是关键的 - 反射，分散，在截止频率和谐振频率的变化，和其他issues可能出现的由于在波导对准不当。使用安全的持有人，以确保可重复的位置。 </li><li>注射器座：它是有用的，具有这样的结构，保持到位，使注射器的前端与槽对准。通过这样做，你可以减少错误的议案，在你的手中的注射器由于在灌装的可能性。 </li></ol> 3。样品制备<ol><li>清洁步骤：拆下的波导。在适当的溶剂中，以除去任何残余物从实验中的波导管的两个板的彻底洗净。用压缩空气吹干。 1.3重新组装。 </li><li>注射器准备。为了达到最佳效果，我们建议使用不同的注射器，每一个材料，以防止交叉污染。如果这是不可能的，在注射器应该也可以用相同的溶剂清洗。 </li><li>适当的填充容积与要测试的液体填充注射器。尽量消除任何气泡。 </li></ol><ol><li>的未开槽的参考波导放置在（2.3）中所描述的装置。参考波形的开槽波导，然后取出。每隔几个小时，这仅仅是必要每个实验的会话期间，取决于时域光谱仪信号的长期稳定性。 </li><li>干净的开槽波导放置在装置中的说明，（2.3） </li><li>的空槽波导的波形。注意：这必须做每次波导除去和清洗。去除和拆卸的方法，可以导致在波导管的几何形状中的非常小的变化。这些变化将会影响绝对谐振频率的空的和填充的槽，但没有观察到的移位，因此，每一个“完整”的测量需要它自己的“空的”参照计算的移位。 </li><li>不动的波导，把充式注射器在持有人。慢慢地填补了凹槽，保持看，填充性好，无气泡或溢出。 （如何，以确定正确的填充量的讨论部分中描述的）以另一个波形。 </li><li>如果系统中有一个以上的槽，继续填充槽并考虑所需的波形。 </li><li>删除波导和清洗（步骤3）中。 </li><li>必要时重复多次。为了获得最佳结果，对每个样品的几个数据集被建议来减少误差。 </li></ol> 5。代表性的成果数据分析这些波形是简单的，并可以按照实验者的通常用于变换到频域的技术。应导致如在图3中所给出的频率谱。这些可以被平方并除以参考波形，得到如图4的功率透射光谱。可以是m为空的和充分的波导的线宽和中心频率的共振easured从这些光谱中，或洛伦兹配合可以进行提高准确率。 由液体引起的谐振移位仅仅是所观察到的中央空和满波导的共振频率之间的差异。将其转换为一个折射率测量，换档和RI之间的关系必须被建立。这可以做实验，或计算进行模拟槽充满了已知的指数9，或分析使用模式的样本匹配技术，8，请按照以下步骤知名指数的样本。一旦建立与RI曲线移位，罗德岛未知样品的测量，可以精确地执行。 有几个特别在此过程中可能发生的错误。气泡或错误的凹槽填充可能会导致噪音或不正确的数据，这就是为什么我们建议为每个SA的多个数据集mple材料。另一种常见的错误是在波导管的位置。如果参考和传感器波导中被放置在完全相同的取向，将任何的反射或其它工件上是相同的，将分满分的透射光谱。如果校准是稍微偏离，反射不会划分和振铃，将观察到的透射光谱中（在图4中可以看出，一些轻微的振铃）。夺回数据如果这是不可取的，这是可能消除这种振铃通过修整的反射出现之前的时域波形，但是这大大降低了的光谱分辨率，因此，折射率的分辨率是有限的，以及。 <img alt="图1" src="/files/ftp_upload/4304/4304fig1.jpg" /> 图1照片，标记与相关部件的波导管。需要注意的是，凹槽不延长电子ntire的波导和结构的长度或宽度被设计成使得安装硬件不会阻碍辐射传播的槽或通道的。 <img alt="图2" src="/files/ftp_upload/4304/4304fig2.jpg" /> 图2。开槽波导的示意图。 <img alt="图3" src="/files/ftp_upload/4304/4304fig3.jpg" /> 图3。 （a）样品的频谱参考波导（黑色），没有液体填充波导（蓝色）的槽，与液体和带槽的波导，在这种情况下，十四烷（红色）。 TE和TE传播模式的截止频率显示，水蒸汽吸收线。（二）特写的空和满槽波导的共振。 <img alt="图4" src=“机构/ files/ftp_upload/4304/4304fig4.jpg”/&gt; 图4。电源的空和满槽波导透射谱。之间的频率差的两个谐振特性的谐振偏移（Δf）的，它涉及的折射率。

<ol>
	<li>Kuswandi, B., Nuriman, ., Huskens, J., Verboom, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+sensing+systems+for+microfluidic+devices:+A+review.">Optical sensing systems for microfluidic devices: A review.</a> Ana. Chim. Acta. 601, 141-155 (2007).</li><li>Zhu, H., White, I. M., Suter, J. D., Zourob, M., Fan, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrated+refractive+index+optical+ring+resonator+detector+for+capillary+electrophoresis.">Integrated refractive index optical ring resonator detector for capillary electrophoresis.</a> Anal. Chem. 79, 930-937 (2007).</li><li>Kurt, H., Citrin, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coupled-resonator+optical+waveguides+for+biochemical+sensing+of+nanoliter+volumes+of+analyte+in+the+terahertz+region.">Coupled-resonator optical waveguides for biochemical sensing of nanoliter volumes of analyte in the terahertz region.</a> Appl. Phys. Lett. 87, 241119 (2005).</li><li>Debus, C., Bolivar, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequency+selective+surfaces+for+high+sensitivity+terahertz+sensing.">Frequency selective surfaces for high sensitivity terahertz sensing.</a> Appl. Phys. Lett. 91, 184102 (2007).</li><li>Harsha, S. S., Laman, N., Grischkowsky, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Q+terahertz+Bragg+rsonances+within+a+metal+parallel+plate+waveguide.">High-Q terahertz Bragg rsonances within a metal parallel plate waveguide.</a> Appl. Phys. Lett. 94, 091118 (2009).</li><li>Mendis, R., Mittleman, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+lowest-order+transverse-electric+(TE1)+and+transverse-magnetic+(TEM)+modes+of+the+parallel-plate+waveguide+for+terahertz+pulse+applications.">Comparison of the lowest-order transverse-electric (TE1) and transverse-magnetic (TEM) modes of the parallel-plate waveguide for terahertz pulse applications.</a> Optics Express. 17, 14839-14850 (2009).</li><li>Mendis, R., Mittleman, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+investigation+of+the+lowest-order+transverse-electric+(TE1)+mode+of+the+parallel-plate+waveguide+for+THz+pulse+propagation.">An investigation of the lowest-order transverse-electric (TE1) mode of the parallel-plate waveguide for THz pulse propagation.</a> JOSA B. 26, A6-A13 (2009).</li><li>Astley, V., McCracken, B., Mendis, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+rectangular+resonant+cavities+in+terahertz+parallel-plate+waveguides.">Analysis of rectangular resonant cavities in terahertz parallel-plate waveguides.</a> Opt. Lett. 36, 1452 (2011).</li><li>Mendis, R., Astley, V., Liu, J., Mittleman, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+microfluidic+sensor+based+on+a+parallel-plate-waveguide+resonant+cavity.">Terahertz microfluidic sensor based on a parallel-plate-waveguide resonant cavity.</a> Appl. Phys. Lett. 95, 171113 (2009).</li><li>Astley, V., Reichel, K., Jones, J., Mendis, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+multichannel+microfluidic+sensor+based+on+parallel-plate+waveguide+resonant+cavities.">Terahertz multichannel microfluidic sensor based on parallel-plate waveguide resonant cavities.</a> Appl. Phys. Lett. , (2012).</li></ol>

没有利益冲突的声明。

应当指出，只是在空腔谐振频率确定被测液体的折射率，而不是在很宽的带宽。这具有几个显着的优点。首先，虽然我们的测量已表征的目的使用的宽带太赫兹源，也可以建立一个等效的传感系统与一个单一的频率THz源与只有一个有限的程度的频率可调谐性，一种方法，可以是便宜得多，并更紧凑。其次，感测的方法可以被并行化，通过将多个槽成一个单一的波导。10，每个槽有一个稍微...

<table border="1"><tbody><tr><td> 的试剂的名称 </td><td> 公司 </td><td> 目录编号 </td><td> 评论（可选） </td></tr><tr><td> 10μl注射器</td><td>汉密尔顿</td><td> 80314 </td><td>高精密注射</td></tr><tr><td>液态烷烃</td><td> Acros Organics公司</td><td></td><td>样品进行校准和测试</td></tr><tr><td></td><td></td><td></td><td>没有特定的设备是必需的。合适的试验材料和溶剂留下实验者的酌情决定。此过程中使用的高精度的注射器中列出在下面的表中，但实验者可能希望使用一个不同的卷或设计的注射器，包括数字注射器以提高精度。本实验中使用的测试烷烃也列出。 </td></tr></tbody></table>

terahertz microfluidic sensing using a parallel-plate waveguide sensor

折射率（RI）传感是一个功能强大的微流体样品进行了广泛的可能的传感器设计，如干涉仪和谐振器1,2的鉴定，检测和监测的无创性和无标记检测技术。大多数现有的RI传感应用集中于生物材料在水溶液中，在可见光和红外的频率，如DNA杂交和基因组测序。在太赫兹频率，应用程序，包括质量控制，监测工业生产过程和传感与检测涉及非极性材料的应用。 折射率传感器在太赫兹政权存在一些潜在的设计，包括光子晶体波导，不对称开口环谐振器，并整合成平行板波导的光子带隙结构。这些设计是基于光学谐振器，如戒指或空洞。这些结构的谐振频率依赖于内或周围的谐振器的材料的折射率。通过监测在谐振频率的变化的样品的折射率可以被准确地测量，而这反过来又可以用来确定一个材料，监测污染或稀释等我们在这里使用这种传感器的设计是基于一个简单的平行板波导6,7。到一个谐振腔（ 图1和图2）的一个面作为加工的矩形槽。当被耦合到的最低阶横向电（TE）模式的波导管中传播的太赫兹辐射，其结果是与一个可调谐的谐振频率的槽6,8的几何形状是依赖于一个单一的强共振特性。该槽可填充有导致移位在所观察到的谐振频率依赖于液体的量的非极性液体的微流体样品的uid中的槽和其折射率9。 我们的技术具有比其他的太赫兹波在它的简单的技术，无论是在制造和实施的优点，因为该过程可以用标准的实验室设备来完成，而不需要一个干净的房间或任何特殊的制造或实验技术。它也可以很容易地扩展到多通道操作通过掺入的多个槽10。在这个视频中，我们将介绍完整的实验过程中，从设计的传感器的数据分析和测定样品折射率。

Watch this Scientific Journal Video about Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor at JoVE.com

Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor

实施折射率传感器的基础上的带槽的平行板波导几何的太赫兹频率的程序在这里被描述。通过监测的波导结构的谐振频率的移位，该方法产生的一个小体积的液体的折射率测量

太赫兹微流控测量中的一个平行板波导传感器

Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic ...

terahertz-microfluidic-sensing-using-a-parallel-plate-waveguide-sensor

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JoVE Core

JoVE Journal

Electrical Engineering

Engineering

Unit 1

Power Transformers

SCIENTISTS IN ACTION

10.7K 次观看.  Rice University. 实施折射率传感器的基础上的带槽的平行板波导几何的太赫兹频率的程序在这里被描述。通过监测的波导结构的谐振频率的移位，该方法产生的一个小体积的液体的折射率测量

视频: Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor

Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters

In this video article we present a detailed demonstration of a highly efficient method for generating terahertz waves. Our technique is based on photoconduction, which has been one of the most commonly used techniques for terahertz generation 1-8. Terahertz generation in a photoconductive emitter is achieved by pumping an ultrafast photoconductor with a pulsed or heterodyned laser illumination. The induced photocurrent, which follows the envelope of the pump laser, is routed to a terahertz radiating antenna connected to the photoconductor contact electrodes to generate terahertz radiation. Although the quantum efficiency of a photoconductive emitter can theoretically reach 100%, the relatively long transport path lengths of photo-generated carriers to the contact electrodes of conventional photoconductors have severely limited their quantum efficiency. Additionally, the carrier screening effect and thermal breakdown strictly limit the maximum output power of conventional photoconductive terahertz sources. To address the quantum efficiency limitations of conventional photoconductive terahertz emitters, we have developed a new photoconductive emitter concept which incorporates a plasmonic contact electrode configuration to offer high quantum-efficiency and ultrafast operation simultaneously. By using nano-scale plasmonic contact electrodes, we significantly reduce the average photo-generated carrier transport path to photoconductor contact electrodes compared to conventional photoconductors 9. Our method also allows increasing photoconductor active area without a considerable increase in the capacitive loading to the antenna, boosting the maximum terahertz radiation power by preventing the carrier screening effect and thermal breakdown at high optical pump powers. By incorporating plasmonic contact electrodes, we demonstrate enhancing the optical-to-terahertz power conversion efficiency of a conventional photoconductive terahertz emitter by a factor of 50 10.

We describe methods for the design, fabrication, and experimental characterization of plasmonic photoconductive emitters, which offer two orders of magnitude higher terahertz power levels compared to conventional photoconductive emitters.

电浆光电导太赫兹发射器的设计，制造和实验表征

In this video article we present a detailed demonstration of a highly efficient method for generating terahertz waves. Our technique is based on ...

科研

工程学

How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to 1.0 Pa. In this application, the SRGs are frequently transported to laboratories for calibration. Events can occur during transportation that change the rotor surface conditions, thus changing the calibration factor. To assure calibration stability, a spring-transport mechanism is often used to immobilize the rotor and keep it under vacuum during transport. It is also important to transport the spring-transport mechanism using packaging designed to minimize the risk of damage during shipping. In this manuscript, a detailed description is given on how to build a robust spring-transport mechanism and shipping container. Together these form a spring-transport package. The spring-transport package design was tested using drop-tests and the performance was found to be excellent. The present spring-transport mechanism design keeps the rotor immobilized when experiencing shocks of several hundred g (g = 9.8 m/sec2 and is the acceleration due to gravity), while the shipping container assures that the mechanism will not experience shocks greater than about 100 g during common shipping mishaps (as defined by industry standards).

Here we describe how to build a robust spring-transport mechanism for a spinning rotor gauge. This device securely immobilizes the rotor and keeps it under vacuum during transportation. We also describe packaging that minimizes the risk of damage during transport. Tests show our design works for typical shocks during transport.

如何建立一个真空Spring的运输包装为纺转子规

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to ...

Fabrication of Nanopillar-Based Split Ring Resonators for Displacement Current Mediated Resonances in Terahertz Metamaterials

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR is not affected by environmental characteristics such as the temperature and pressure surrounding the resonator. Electromagnetic radiation in THz frequencies is biocompatible, which is a critical condition especially for the application of the biomolecular sensing. However, the quality factor (Q-factor) and frequency responses of traditional thin-film based split ring resonator (SRR) MMs are very low, which limits their sensitivities and selectivity as sensors. In this work, novel nanopillar-based SRR MMs, utilizing displacement current, are designed to enhance the Q-factor up to 450, which is around 45 times higher than that of traditional thin-film-based MMs. In addition to the enhanced Q-factor, the nanopillar-based MMs induce a larger frequency shifts (17 times compared to the shift obtained by the traditional thin-film based MMs). Because of the significantly enhanced Q-factors and frequency shifts as well as the property of biocompatible radiation, the THz nanopillar-based SRR are ideal MMs for the development of biomolecular sensors with high sensitivity and selectivity without inducing damage or distortion to biomaterials. A novel fabrication process has been demonstrated to build the nanopillar-based SRRs for displacement current mediated THz MMs. A two-step gold (Au) electroplating process and an atomic layer deposition (ALD) process are used to create sub-10 nm scale gaps between Au nanopillars. Since the ALD process is a conformal coating process, a uniform aluminum oxide (Al2O3) layer with nanometer-scale thickness can be achieved. By sequentially electroplating another Au thin film to fill the spaces between Al2O3 and Au, a close-packed Au-Al2O3-Au structure with nano-scale Al2O3 gaps can be fabricated. The size of the nano-gaps can be well defined by precisely controlling the deposition cycles of the ALD process, which has an accuracy of 0.1 nm.

A protocol for the design and fabrication of a novel nanopillar-based split ring resonator (SRR) is presented.

基于纳米柱裂环谐振器的研制为位移电流共振介导太赫兹超材料

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR ...

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Probing remote matter with laser light is a ubiquitous technique used in circumstances as diverse as laser-induced breakdown spectroscopy and barcode scanners. In classical optics, the intensity that can be brought to bear on a remote target is limited by the spot size of the laser at the distance of the target. This spot size has a lower bound determined by the diffraction limit of classical optics. However, amplified femtosecond laser pulses generate intensity sufficient to modify the refractive index of the ambient air and undergo self-focusing. This self-focusing effect leads to the generation of highly intense laser filaments which maintain their intensity and small sub-millimeter diameter size at distances well beyond the classical Rayleigh length. Such intensity provides the capability of remote scanning, imaging, sensing, and spectroscopy with enhanced spatial resolution. We describe a technique for generating filaments with a femtosecond regenerative chirped-pulse amplifier, and for using the resulting filament to conduct imaging and spectroscopic measurements at remote distances of at least several meters.

High-intensity femtosecond pulses of laser light can undergo cycles of Kerr self-focusing and plasma defocusing, propagating an intense sub-millimeter-diameter beam over long distances. We describe a technique for generating and using these filaments to perform remote imaging and sensing beyond the classical diffraction limits of linear optics.

飞秒激光丝在亚衍射有限成像和遥感中的应用

Probing remote matter with laser light is a ubiquitous technique used in circumstances as diverse as laser-induced breakdown spectroscopy and barcode ...

Terahertz Imaging and Characterization Protocol for Freshly Excised Breast Cancer Tumors

This manuscript presents a protocol to handle, characterize, and image freshly excised human breast tumors using pulsed terahertz imaging and spectroscopy techniques. The protocol involves terahertz transmission mode at normal incidence and terahertz reflection mode at an oblique angle of 30&#176;. The collected experimental data represent time domain pulses of the electric field. The terahertz electric field signal transmitted through a fixed point on the excised tissue is processed, through an analytical model, to extract the refractive index and absorption coefficient of the tissue. Utilizing a stepper motor scanner, the terahertz emitted pulse is reflected from each pixel on the tumor providing a planar image of different tissue regions. The image can be presented in time or frequency domain. Furthermore, the extracted data of the refractive index and absorption coefficient at each pixel are utilized to provide a tomographic terahertz image of the tumor. The protocol demonstrates clear differentiation between cancerous and healthy tissues. On the other hand, not adhering to the protocol can result in noisy or inaccurate images due to the presence of air bubbles and fluid remains on the tumor surface. The protocol provides a method for surgical margins assessment of breast tumors.

Freshly excised human breast cancer tumors are characterized with terahertz spectroscopy and imaging following fresh tissue handling protocols. Tissue positioning is taken into consideration to enable effective characterization while providing analysis in a timely manner for future intraoperative applications.

新切除乳腺癌肿瘤的Terahertz成像和表征协议

This manuscript presents a protocol to handle, characterize, and image freshly excised human breast tumors using pulsed terahertz imaging and spectroscopy ...

Measuring Sub-23 Nanometer Real Driving Particle Number Emissions Using the Portable DownToTen Sampling System

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future combustion engine vehicle technology may emit large amounts of sub-23 nm particles. The Horizon 2020 funded project DownToTen (DTT) developed a sampling and measurement method to characterize particle emissions in this currently unregulated size range. A PN measurement system was developed based on an extensive review of the literature and laboratory experiments testing a variety of PN measurement and sampling approaches. The measurement system developed is characterized by high particle penetration and versatility, which enables the assessment of primary particles, delayed primary particles, and secondary aerosols, starting from a few nanometers in diameter. This paper provides instruction on how to install and operate this Portable Emission Measurement System (PEMS) for Real Drive Emissions (RDE) measurements and assess particle number emissions below the current legislative limit of 23 nm.

Presented here is the DownToTen (DTT) portable emission measurement system to assess real driving automotive emissions of sub-23 nm particles.

使用便携式 DownToTen 采样系统测量低于 23 纳米实际驱动粒子数排放

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future ...

Mechanoluminescent Visualization of Crack Propagation for Joint Evaluation

In this study, methods for the mechanoluminescent (ML) visualization of crack propagation and mechanical behavior to evaluate adhesive joints are demonstrated and explained. The first step involved sample preparation; an air spray was used to apply ML paint to the surface of the adhesive joint specimens. The performance of the ML sensor was described to examine the measurement conditions. The results of ML sensing during a double cantilever beam (DCB) test and a lap-shear (LS) test are demonstrated as these are the most frequently and widely used methods for evaluating adhesives. Originally, it was difficult to directly quantify the crack tip and strain/stress distribution and concentration because the crack tip was too small, and the effects of the strain could not be observed. The mechanoluminescence, crack propagation, and mechanical behavior during mechanical testing can be visualized via the ML pattern during the adhesive evaluation. This allows for the recognition of the precise position of the crack tips and other mechanical behaviors related to structural failure.

In this study, a protocol is presented that describes the use of mechanoluminescent (ML) visualization for monitoring crack propagation and mechanical behavior during adhesive joint evaluation testing.

裂纹扩展的机械发光可视化用于联合评估

In this study, methods for the mechanoluminescent (ML) visualization of crack propagation and mechanical behavior to evaluate adhesive joints are ...

Fabrication of a Fabry-P&#233;rot Etalon for Application in Trace-Gas Spectroscopy

Fabrication of a Low-Cost, Fiber-Coupled, and Air-Spaced Fabry-P&#233;rot Etalon

Fabry-P&#233;rot etalons (FPE) have found their way into many applications. In fields such as spectroscopy, telecommunications, and astronomy, FPEs are used for their high sensitivity as well as their exceptional filtering capability. However, air-spaced etalons with high finesse are usually built by specialized facilities. Their production requires a clean room, special glass handling, and coating machinery, meaning commercially available FPEs are sold for a high price. In this article, a new and cost-effective method to fabricate fiber-coupled FPEs with standard photonic laboratory equipment is presented. The protocol should serve as a step-by-step guide for the construction and characterization of these FPEs. We hope this&#160;will enable researchers to conduct fast and cost-effective prototyping of FPEs for various fields of application. The FPE, as presented here, is used for spectroscopic applications. As shown in the representative results section via proof of principle measurements of water vapor in ambient air, this FPE has a finesse of 15, which is sufficient for the photothermal detection of trace concentrations of gases.

Author Spotlight: Fabrication of a Low-Cost, Fiber-Coupled, and Air-Spaced Fabry-P&#233;rot Etalon  

This protocol describes the construction of a low-cost, discrete, fiber-coupled, and air-spaced Fabry-Perot etalon with various applications, such as in trace-gas spectroscopy. The fabrication is possible in any facility with standard optical laboratory equipment available.

制造低成本、光纤耦合和空气间隔的法布里-佩罗标准具

Fabry-P&#233;rot etalons (FPE) have found their way into many applications. In fields such as spectroscopy, telecommunications, and astronomy, FPEs are ...

用于电容式压力传感的基于微流体通道的软电极

Microfluidic Channel-Based Soft Electrodes and Their Application in Capacitive Pressure Sensing

Flexible and stretchable electrodes are essential components in soft artificial sensory systems. Despite recent advances in flexible electronics, most electrodes are either restricted by the patterning resolution or the capability of inkjet printing with high-viscosity super-elastic materials. In this paper, we present a simple strategy to fabricate microchannel-based stretchable composite electrodes, which can be achieved by scraping elastic conductive polymer composites (ECPCs) into lithographically embossed microfluidic channels. The ECPCs were prepared by a volatile solvent evaporation method, which achieves a uniform dispersion of carbon nanotubes (CNTs) in a polydimethylsiloxane (PDMS) matrix. Compared to conventional fabrication methods, the proposed technique can facilitate the rapid fabrication of well-defined stretchable electrodes with high-viscosity slurry. Since the electrodes in this work were made up of all-elastomeric materials, strong interlinks can be formed between the ECPCs-based electrodes and the PDMS-based substrate at the interfaces of the microchannel walls, which allows the electrodes to exhibit mechanical robustness under high tensile strains. In addition, the mechanical-electric response of the electrodes was also systematically studied. Finally, a soft pressure sensor was developed by combining a dielectric silicone foam and an interdigitated electrodes (IDE) layer, and this demonstrated great potential for pressure sensors in soft robotic tactile sensing applications.

作者聚焦：基于微流体通道的软电极及其在电容式压力传感中的应用  

Flexible electrodes have a wide range of applications in soft robotics and wearable electronics. The present protocol demonstrates a new strategy to fabricate highly stretchable electrodes with high resolution via lithographically defined microfluidic channels, which paves the way for future high-performance soft pressure sensors.

基于微流控通道的软电极及其在电容式压力传感中的应用

Flexible and stretchable electrodes are essential components in soft artificial sensory systems. Despite recent advances in flexible electronics, most ...