Ion beam erosion of rough glass surfaces.

Rough ground samples of fused silica were irradiated with an argon ion beam. At high angles of incidence the randomly pitted surface structure was converted to a striated surface. An explanation for the development of the striated topography is based on the dependence of sputtering rate on the localized angle of incidence of the ions with respect to individual surface features. Experimental conditions for removal of isolated surface defects and the conditions under which a smooth surface may be produced by ion erosion are discussed.