基于激光捕捉技术的微细加工

【作者】 王晓娜；

【导师】 白剑；

【作者基本信息】 浙江大学 ， 测试计量技术及仪器， 2004， 硕士

【摘要】 本文首先介绍了现有微细加工方法并对其进行比较，提出基于激光捕捉(Laser Trapping)实现微细加工的新技术。 激光捕捉技术又形象地被称为光镊，它是激光光压的主要应用之一，是利用一束高度会聚的激光形成的三维势阱实现对微小粒子(亚微米到数十微米大小)精确定位和操控。文中综述了这一新型技术的研究现状，目前已广泛应用于生物，医学、物理和化学等领域中，但在微细加工应用方面的研究国内外尚处于起步阶段。R．C．GAUTHIER在1997年首次提出将“光镊”应用于微加工领域，可实现对微小器件的非接触式移动、操纵和组装，但R．C．GAUTHIER未提到将它应用于表面或体微细加工。文中创新性的提出将几个微米的高强度微粒子(如金刚石、碳化硅、石英等)作为微加工工具，在光镊的驱动下在加工表面产生移动、高速转动及振动，从而完成微米乃至纳米级的加工任务。这种新型加工技术具有易实现、易控制、高加工精度、可实现三维加工的四大特点，克服了现有加工方法的缺点。 本文从理论和实验两方面研究对其进行了论证。理论研究以量子光学为理论基础，利用几何光学和动量守恒定律建立了仿真模型，实现了对任意形状米氏粒子受力的计算机仿真。了解了各项参数对粒子捕捉力和光力矩的影响，确定了最佳捕捉条件。实验研究以理论研究为基础，建立了满足最佳捕捉条件时的实验装置，并在国内首次实现了在液体中对高强度粒子的捕捉，并使被捕捉的粒子在加工面上反复移动及转动，获得了2nm的表面微细刻痕。同时还通过实验比较，定性分析了最佳加工条件(如激光功率和加工表面参数)。更多还原

【Abstract】 In this dissertation, kinds of methods of micro-machining is introduced, and compared with each other. Based on it, Micro-machining based on Laser Trapping of Micro-sized particles is presented.Laser Trapping technology, called Optical Tweezers, is a primary application of laser radiation pressure. When a tight focused laser beam passes through a micro-particle, the particle will be orientated and controlled with high accuracy, due to the three-dimensional optical gradient force. This paper summarizes current investigation on this novel technology. Laser Trapping is already widely used in biology, medicine, physics, chemistry, and so on, but its application to micro-machining is just at the beginning. In 1997, this idea was presented by R.C.GAUTHIER for the first time. He predicated that the non-contact controlled displacement ,manipulation and assembly of micro-machines could be implemented by Laser Trapping technology. However, R.C.GAUTHIER didn’t find out its application to surface or bulk micro-machining. We innovate that micro-machining is implemented by cutting the work piece using the micro-particles trapped by the focused laser beam. The micro-particles made of diamond or silica can not only be moved and pushed,but also be rotated and vibrated by the radiation pressure induced by the laser beam. Therefore they can be used as micro-machining tools. This novel technology possesses many virtues. It can not only be implemented and controlled simply but also fulfill three-dimensional machining with high precision, which is not achievable by conventional micro-machining technologies.Theory and experiment of Micro-machining based on Laser Trapping of micro-sized particles are studied in detail . Based on quantum optics , mathematical model of laser trapping on Mie micro-particles is established using geometryl optics and momentum conservation law, and the computer simulation for laser trapping on arbitrary shaped-micro-particles is realized by numerical analysis. By simulation, we know how each parameter affects trapping force and optical torque and to ascertain the best trapping conditions. This paper introduces the optical system for laser trapping, with which highrigidity micro-particles in liquid can be trapped and the machining trace of 2nm on workpiece surface is first attained in china. By experimental analysis, the qualitative analysis of the best machining conditions ,such as laser power and machining floor ,is obtained.更多还原