Flat Polishing
REO uses techniques such as continuous polishing and double-side polishing to produce optical surfaces of exceptional flatness. Double-side polishing is used to efficiently produce plane-parallel surfaces of up to 250mm diameter with typical flatness levels of approximately 20nm rms per cm of diameter.
Continuous polishing consists of holding parts in a ring-lap configuration typically on a table made of pitch and is used to achieve much higher flatness levels, approximately 3nm rms per cm of diameter, on parts up to 250mm diameter.