In process metrology of aspheric optical surfaces during sub-aperture polishing process

The fabrication of complex aspheric and freeform surfaces are possible with accurate iterative metrology feedback during correcting polishing process. The tool path of the machine is generated based on the measured surface data for corrective material removal. The computer controlled polishing machines are compatible with various metrology tools. This paper presents annular null based interferometric in- process metrology for deterministic corrective polishing for aspheric surface of infrared optical material.