Experimental study on absolute test of spherical surfaces with shift-rotation method

Abstract

Absolute test of spherical surfaces has been widely used because of increased demand on metrology accuracy. We demonstrate the validity of an absolute test method with shift and rotation procedure that has been proposed earlier. The method relies on the decomposition of the surface deviations into rotationally asymmetric and symmetric components. The surface deviation measured with the absolute test method of shift-rotation agrees well with that of two-sphere method. The difference of rms is ~0.4nm while the PV is very sensitive to environmental effects.