Novel Polishing Methods

This chapter briefly discusses some novel polishing methods for optical fabrication. In many optical fabrication processes, conventional polishing is first used to get as close as possible to the desired surface figure. Magnetorheological finishing (MRF) is a novel polishing process for deterministic surface figure correction. Similar to MRF, float polishing is a finishing technique that operates in hydrodynamic mode. The convergent polishing allows for polishing workpieces in a single iteration using a single set of polishing parameters, regardless of the initial shape of the workpiece and without the need for initial and in-process surface figure metrology. Subaperture polishing methods have greatly expanded the ability to finish asymmetric optics, such as aspheres, and other complex-shaped optics. Ion beam figuring (IBF) is an ultraprecision, subaperture surface-finishing method that started in the mid-1980s. An unique polishing method, called tumble finishing, is used for smoothing or locally planarizing the surface of more-complex-shaped workpieces.