Microfabrication Technology Based On Laser Capture

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.