The increased demand for aspheric surfaces in optical systems has required refinements and advances in optical shop technology. Air gauges have been used to measure aspheric surfaces in prepolished and polished conditions to accuracies on the order of one wavelength of visible light. Small, synchronously driven laps have been used in the polishing and figuring of aspheric surfaces with good results regarding speed, accuracy, and smoothness. Both techniques provide interesting possibilities for future development.
George Random and Edward P. Wallerstein, "Air Gauge Measurement and Driven Lap Polishing in the Production of Aspheric Surfaces," Appl. Opt. 5, 737-740 (1966)