Subsurface Damage in Microgrinding Optical Glasses

LLE Review, Volume 73 45 In cold processing of optical glasses by microgrinding,1,2 the resulting brittle-material-removal rate induces a cracked layer near the glass surface, referred to as subsurface damage (SSD). [Editor’s note: The acronym for subsurface damage (SSD) used in this article should not be confused with its more common use as an acronym for smoothing by spectral dispersion.] In addition, there is a corresponding surface microroughness (SR), often found to increase in proportion to SSD, as originally observed by Preston.3 SSD is a statistical measure and not necessarily equal to the flaw depth that may control mechanical strength of the brittle surface.