Polishing of Sapphire for Optical Applications

目前制造蓝宝石的工艺会在生长的蓝宝石毛坯中引入许多缺陷，如模痕和生长伪影。因此，这些材料在用于光学之前需要抛光。第一阶段的目标是开发一种高质量、高速度、低成本的蓝宝石光学抛光技术。目前用于抛光蓝宝石的两种方法是：机械和机械化学，这两种方法都涉及刮削，研磨和使用磨料，如金刚石或胶体二氧化硅。这些方法都是昂贵的，因为抛光需要很长时间。此外，由于施加机械压力，在抛光界面处产生热量，留下影响光学性能的缺陷。第一阶段将通过使用双阶段非接触方法来消除蓝宝石的平面层，从而在平面和弯曲坯料中实现埃级的表面粗糙度，从而建立概念验证。将对抛光后的样品进行光学表征，并与加工参数相关联。在第二阶段，我们建议将这种技术扩展到光学圆顶。该技术还可用于涉及光学元件的其他应用，如激光腔镜、激光束镜、透镜、具有高光传输的窗口、软盘驱动器和磁盘驱动器中的组件。**

9360761 Sudarshan Current processes for manufacturing sapphire introduce a number of defects such as die marks and growth artifacts in the as-grown sapphire blank. Thus these materials will need to be polished prior to use in optics. The objective of this Phase I effort is to develop a high quality, high speed, cost effective technique for polishing sapphire based optics. The two methods currently used for polishing sapphire are: mechanical and mechanochemical, both of which involve scraping, grinding and using abrasives such as diamond or colloidal silica. These methods are expensive because of the long times required for polishing. Further, due to the application of mechanical pressure, heat is generated at the polishing interface leaving behind defects that affect optical performance. Phase I will establish the proof of concept by using a dual stage non-contact method to remove planar layers of the sapphire thus achieving surface roughness on the order of angstroms in both flat and curved blanks. Optical characterization will be performed on the polished samples and correlated to the processing parameters. In Phase II, we propose expanding this technique for optical domes. This technique can also be used for other applications involving optical components such as laser cavity mirrors, laser beam mirrors, lenses, windows with high optical transmission, components in floptical disk drives and magnetic disk drives. **