Polishing of Sapphire for Optical Applications

9360761 Sudarshan 当前的蓝宝石制造工艺会在生长的蓝宝石毛坯中引入许多缺陷，例如模具痕迹和生长伪影。因此，这些材料在用于光学器件之前需要进行抛光。第一阶段工作的目标是开发一种高质量、高速且具有成本效益的技术，用于抛光蓝宝石光学器件。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擦、研磨和使用金刚石或胶体二氧化硅等磨料。这些方法由于抛光需要很长时间，因此价格昂贵。此外，由于施加机械压力，抛光界面处会产生热量，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去除蓝宝石的平面层来建立概念验证，从而在平面和曲面毛坯中实现埃数量级的表面粗糙度。将对抛光样品进行光学表征，并将其与加工参数相关联。在第二阶段，我们建议将这项技术扩展到光学圆顶。该技术还可用于涉及光学组件的其他应用，例如激光腔镜、激光束镜、透镜、高光传输窗口、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. **