Suratwala Tayyab, Steele Rusty, Feit Michael, Dylla-Spears Rebecca, Desjardin Richard, Mason Dan, Wong Lana, Geraghty Paul, Miller Phil, Shen Nan
Lasers, Optics, & Targets for the National Ignition Facility, Lawrence Livermore National Laboratory;
Lasers, Optics, & Targets for the National Ignition Facility, Lawrence Livermore National Laboratory.
J Vis Exp. 2014 Dec 1(94):51965. doi: 10.3791/51965.
Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~λ/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.
收敛抛光是一种用于对平面和球面玻璃光学元件进行精加工的新型抛光系统和方法。在该方法中，工件无论其初始形状（即表面形状）如何，在单次抛光迭代中，在一组固定不变的抛光参数下，都能收敛到具有优异表面质量的最终表面形状。相比之下，传统的全孔径抛光方法需要多次（通常较长）的迭代循环，包括抛光、计量和工艺调整，才能达到所需的表面形状。收敛抛光工艺基于工件与抛光垫高度不匹配导致压力差的概念，该压力差会随着去除量的增加而减小，从而使工件收敛到抛光垫的形状。收敛抛光工艺的成功实施是多种技术相结合的结果，这些技术可消除所有非均匀空间材料去除源（工件与抛光垫不匹配除外），以实现表面形状收敛，并减少系统中流浪颗粒的数量，从而降低划痕密度和粗糙度。收敛抛光工艺已被证明可用于在各种玻璃材料上制造各种形状、尺寸和长宽比的平面和球面。实际影响是，可以更快、更重复地制造高质量光学元件，减少计量和劳动力，从而降低单位成本。在本研究中，具体描述了收敛抛光方案，即在直径81厘米的抛光机上，对边长26.5厘米的熔融石英平面从精磨表面开始进行抛光，每个表面抛光4小时后达到约λ/2的抛光表面形状。
