Research On Ultrafast Laser Polishing Monocrystalline-Silicon

With the development of related disciplines, achieving ultra smooth polish of optical surface has become an important research in the precision machining. Laser polishing technology as a surface handle technology with good polishing effect and less thermal effect, has an unparalleled advantage in high-precision polishing relative to conventional polishing techniques.There were discussed in this article that the mechanism of ultrafast laser for optical materials, polishing system structures, experimental design, implement and test data analysis. Build a dynamic model of ultrafast laser polishing quartz, explore the ultrafast laser polishing process. In the experiment, the laser source uses fs and ps laser, utilizes digital microscope and surface profile to detect the surface morphology and roughness. And the effects that laser energy density, overlap spot rate and defocusing amount to ultrafast laser polishing was Analysed. It can Analysis the factors share of the weight in the polishing, affect changes in the level of each factor to the polishing effect intuitive respectively by orthogonal experimental design and univariate analysis. The method combines two experimental parameters can optimize affect parameters more scientific and reasonable, Use univariate and orthogonal experiment method polished quartz directly and material samples coated with a sacrificial layer. Finally it has compared the two polished results. The following conclusions can be reached in this article:1) Derived The kinetic model equation of ultrafast laser effecting optical material, as the energy density is changed, the etching depth of the material is changed non-linearly.2) Using the orthogonal experiment method, it is educe that laser energy density shares max-weight in whole polishing process compared. Because the range of laser energy density is bigger than surplus two factor.3) It is can obtain that laser energy density is the biggest affect to the polishing effect during the laser energy density, overlap spot rate and defocusing amount by orthogonal experimental optimization design, because the weights of laser energy density is larger than another factors.4) Using ultrafast laser system polish quartz crystal that surface is coated with a sacrificial layer of material, it can get a better polishing effect than polish directly.