Forming tiny 3D structures for micro- and nanofluidics
Forming tiny 3D structures for micro- and nanofluidics
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形成微纳米流体的微小 3D 结构
DOI：
10.1117/2.1200612.0510
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
S. Juodkazis
中科院分区：
文献类型：
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作者：
S. Juodkazis
具有预先设计的光学功能的三维结构，如波导、光子晶体和微机械部件，可以组合成具有多种功能的单个微型器件。研究人员已经制造出结合了光学和微流控功能的微流控装置和传感器。然而，对于这些器件的实际实施，需要提高3D激光微细加工和纳米加工方法的生产效率。我们预计，类似于曝光和显影的摄影过程的两步法将提供最有效的解决方案：首先，通过干涉和/或直接激光写入对样品进行无掩模曝光，以记录结构，然后进行湿处理，以恢复写入的3D结构。这种制造路线符合批处理，这通常是任何实际实施所需要的。为了将具有高亚波长空间分辨率的光-物质相互作用局部化以用于材料的3D结构，我们需要一个每脉冲提供高辐照度的激光光源。很久以前就很明显，飞秒激光脉冲对于这项任务是必不可少的，因为它们能够以很小的脉冲能量产生巨大的辐照度(大约每平方厘米1太瓦)，同时限制辐射点周围的热影响区域。射流微设备和微全分析系统(μ-TAS)有望在生物医学研究和诊断中得到越来越多的应用。3D体系结构允许更多的集成度和紧凑性，以及由于可靠地识别特定化合物和分子所需的少量分析物而提高了灵敏度。通过组合光学、电气和流体系统，可以增强μTAS设备的功能和多功能性。因此，需要较高的光学透过率，特别是对紫外光的透过率，因为紫外光可以激发分析物的荧光。对于电泳应用，宿主介质必须具有高电阻率图1。螺线结构中罗丹明溶液的光致发光的共焦3D图像。3螺线是在紧聚焦条件下通过3D直接激光写入合成石英Viosil中的，使用数值孔径为1.35的物镜。使用180fs脉冲的800 nm照射，以等于可观察光化的两个阈值的脉冲能量，在脉冲位置之间以200 nm的间隔扫描体积。然后用硝酸和氟化氢的水溶液对修饰区域进行刻蚀，螺旋深度为0−62μm。
Three-dimensional structures with predesigned optical functions such as waveguides, photonic crystals, and micromechanical parts can be combined into single microdevices with a number of functions. Researchers have made microfluidic devices and sensors that combine optical and microfluidic functions. For practical implementation of these devices, however, the current efficiency of production needs to be increased for 3D laser microfabrication and nanofabrication methods. We expect that a two-step approach—similar to the photographic process of exposure and development—will offer the most effective solution: first, subjecting the sample to a maskless exposure by interference and/or direct laser writing to record the structure, then wet processing to retrieve the written 3D structure. This fabrication route is compliant with batch processing, which is usually required for any practical implementation. To localize a light-matter interaction with high sub-wavelength spatial resolution for 3D structuring of materials, we need a laser source that provides a high irradiance per pulse. It became obvious long ago that femtosecond laser pulses are indispensable for this task, due to their ability to create a huge irradiance(of about a terawatt per square centimeter) with a small pulse energy, while limiting the thermally affected region around the irradiation spot. Fluidic microdevices and micro total analysis systems (μTAS) are expected to find an increasing number of applications in biomedical research and diagnostics. 3D architectures allow more integration and compactness, as well as increased sensitivity due to the small amount of analyte necessary to reliably recognize specific compounds and molecules. The function and versatility of μTAS devices can be augmented by combining optical, electrical, and fluidic systems. Thus, high optical transmissivity—especially to UV light, which can excite fluorescence of an analyte—is required. For electrophoretic applications, the host medium must have high electrical resistivity Figure 1. A confocal 3D image of photoluminescence from a rhodamine solution within a spiral structure.3 The spiral was written in the synthetic quartz Viosil by 3D direct laser writing at tight focusing conditions, using an objective lens of a numerical aperture of 1.35. Using 800nm irradiation with 180fs pulses, the volume was scanned with a separation of 200nm between pulse locations, at pulse energy equal to the two thresholds of an observable photomodification. Then the modified areas were etched with an aqueous solution of HNO3 and HF.4 The spiral depth spans 0− 62μm.