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题名	飞秒激光在三维光流功能集成中的应用
作者	何飞
学位类别	博士
答辩日期	2010
授予单位	中国科学院上海光学精密机械研究所
导师	程亚
关键词	飞秒激光 激光材料加工 微流体 微光学 光流体 双光子激发
其他题名	Application of Femtosecond Laser Micromachining for 3D Optofluidic Integrations
中文摘要	光流控技术是指一类融合微流控学和微光学技术结合成新颖的功能器件和系统，主要特点在于结构的可调化，功能的集成化和系统的微型化。光流控芯片具有低消耗、高效率和高灵敏度等传统生化分析系统无可比拟的优点，目前已在生物学、化学和医药科学等领域掀起一场重大革命。当前的微制造技术主要借助了传统半导体光刻的方法，它在材料表面微结构的制备上已经具有相当成熟的工艺，然而对于全三维微结构的制备，还需要一系列诸如层叠和熔接等复杂的步骤。此外，光流体微结构在同一基底材料上的三维集成也向当前的微纳加工制造技术提出重大挑战。 近年来，超快光学学科的快速发展已推动光与物质相互作用进入高度非线性领域。应运而生的飞秒激光微加工技术以其突破衍射极限的加工精度和具有对透明材料三维加工的能力等优点在当代微制造领域中独树一帜，已在微流体、微光学、微电子和微机械等领域的应用中崭露头角，并在多功能集成微芯片制备技术中显示出极大优势。飞秒激光微加工技术发展近20年，目前依然存在诸多亟待解决的问题。例如，基于激光直写的逐点扫描工作方式在复杂三维结构制备中将显得异常耗时，效率低下；激光直写时横向和纵向分辨率存在较大差异，难以形成圆形对称横截面型，严重阻碍了它在光学流体器件加工中的应用；最后，如何利用飞秒激光微加工这一独特技术来实现复杂功能（诸如光、流、电、机等）的高度集成也是该研究领域的一大热点。本文致力于解决上述若干技术问题，重点研究了飞秒激光微加工技术在微光学和微流体芯片制备中的应用，主要包括如下内容： （1）提出玻璃拉丝辅助飞秒激光加工技术，特别是演示了通过飞秒激光直写、化学腐蚀和玻璃拉丝等技术在石英玻璃中制备出均匀微流体通道。此外，辅助的玻璃拉丝过程极大地降低了所制得微流体通道的内壁粗糙度，并且还实现了厘米量级三维微流体通道（纵横比大于1,000）； （2）将火焰抛光技术引入飞秒激光微加工并在石英玻璃芯片上制备出极高光学质量的微透镜，该透镜的成像分辨率接近光学衍射极限。此外还展示了该透镜作为非线性成像物镜在光学层析显微成像上的应用，实验测量其横向和轴向分辨率分别为1.7 m和12.3 m； （3）利用飞秒激光直写技术在玻璃芯片表面制备出微流体光波导,为了研究光流控芯片的可调谐特性，通过混合多种透明流体调节液芯折射率，可以形成模式可动态切换的微流体光波导； （4）为了改善飞秒激光直写的轴向分辨率和横截面特性，将时间聚焦脉冲整形技术引入飞秒激光微加工领域，实现了具有三维对称光强分布的球形聚焦光斑， 并成功演示了利用该方法制备出各方向维度上均具有圆形对称横截面型的微流通道和光波导； （5）为了提高飞秒激光的加工效率，提出一种飞秒激光线聚焦和时间调制相结合的线扫描加工方法，并展示了该方法在Foturan玻璃中快速制备体光栅的应用，与传统的飞秒激光紧聚焦点扫描加工方式相比，刚方法将加工效率提高了数百倍。
英文摘要	Optofluidics refers to a kind of novel functionalities and systems centered on the marriage of optics and fluidics. Integration, miniaturization and reconfigurability are major advantages associated with optofluidics. Compared with traditional systems, optofluidics allows for performing chemical and biological analyses with low sample and reagent consumption, high speed of analysis and high sensitivity, and has created a revolution in chemical, biological and medical sciences. Although traditional optical lithography technique has lent ease to the fabrication of a variety of surface microstructures, complicated processes including multilayer stacking and substrates fusing are required when it comes to true three-dimensional (3D) microstructuring. Moreover, 3D integration of microoptics and microfluidics in a single chip represents a formidable challenge to current micro/nano fabrications. In recent decades, the light-matter interactions have been driven into a highly nonlinear area by the rapid development of ultrashort optics. Typically, current femtosecond laser micromachining technique raises the intriguing possibilities of the creation of microoptics, microfluidics, microelectronics and micromechanics, and exhibits promise for their 3D integrations in a single chip. This technology is clearly outpacing any other existing fabrication method for its super resolution that can break through the optical diffraction limits high-precision, and capability of true three dimensional (3D) micro-structuring in transparent materials. Despite of 20 years development, this technology is still confronted with some problems to be resolved urgently. For instance, traditional laser direct write method builds 3D structures point-by-point in a sequential fashion; the low fabrication speed prevents its use in high-throughput manufacturing. Moreover, the general transverse write method (i.e., the writing direction perpendicular to the laser propagation direction) intrinsically results in elliptical cross sections, which is unfavorable for many practical applications, such as writing optical waveguides or fabricating microchannels with circular cross sections. In addition, 3D integration of multifunctionalities, including microoptics, microfluidics, microelectronics, micromechanics and so on, is another hot topic of this field. This dissertation aims to address the above technical issues, and mainly investigate the applications of femtosecond laser micromachining for microfluidics and microoptics. Following are the main contents of the dissertation: First, a glass drawing method is proposed to facilitate femtosecond laser micromachining of microfluidics channels in glass material. In particular, fabrication of homogeneous microfluidic channels in fused silica by femtosecond laser direct writing, followed by wet chemical etching and glass drawing is demonstrated. Additionally, the glass drawing process significantly reduces the inner surface roughness of the fabricated channels, and centimeter-level microfluidic channels with an aspect ratio above 1000 can be realized. For the creation of microoptics, a way of flame polishing is introduced for the fabrication of a microlens on a fused silica chip with excellent optical performance by femtosecond laser microfabrication. The fabricated microlens can offer a high resolution approaching the optical diffraction limit. Moreover, two-photon excitation of fluorescence with the fabricated microlens is demonstrated. The lateral and axial resolutions of fluorescence are measured to be 1.7 and 12.3 m, respectively. In the next place, fabrication of microfluidic optical waveguide on the glass surface is realized using femtosecond laser direct write. To characterize the tunability of optofluidics, it is demonstrated that either a multimode or a single-mode waveguide can be achieved by controlling the refractive index of the liquid. To improve the axial fabrication resolution as well as cross sectional features, a solution by spatiotemporally focusing of the femtosecond laser beam is provided to achieve 3D symmetric spherical intensity distribution of the focal spot. Fabrication of microfluidic channels and optical waveguides with circular cross-sectional shapes in glass chips using this method is successfully demonstrated. Finally, for the sake of high throughput fabrication, a line-by-line scan technique using a modulated femtosecond laser focused with cylindrical lenses is proposed. In particular, rapid fabrication of optical volume gratings in Foturan glass using this technique is demonstrated. It is estimated that the fabrication efficiency can be improved by hundreds of times, compared with traditional point-by-point direct write method.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15638]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	何飞. 飞秒激光在三维光流功能集成中的应用[D]. 中国科学院上海光学精密机械研究所. 2010.

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