Nanometer-scale characteristics of polycrystalline YAG ceramic polishing

Polycrystalline yttrium aluminum garnet (YAG) ceramics used as laser gain media require nanometer-scale surface geometries to minimize light scattering. Generally, uneven material removal between grains and excessive material removal at the grain boundaries retards smoothing of the ceramic surfaces. This paper describes the effects of the mechanical properties and polishing tool structures on the tool contact against the target surface during polishing. This, in addition to the abrasive type and size, influences the polishing characteristics, especially the material removal at the grain boundaries, the grain enhancement, the grain dislodgement, and the resulting nanometer-scale geometries of the polished surfaces.