Wavelength-dispersed optical-line scanning super-resolution interferometry for fast measurement of precision surface

A new precision surface measurement technology which is based on wavelength-dispersed optical-line scanning interferometry and is endowed with both vertical super-resolution and lateral super-resolution is proposed. The light from a broadband light source is dispersed by a blazed grating to be an optical line scanning the surface to realize fast three dimensional (3D) surface measurement. Vertical super-resolution of less than 1 nm is obtained by the means of optical interferometry. By employing an optical amplitude pupil filter, the lateral resolution in one direction is achieved to be less than 0.5 μm. And by expanding the interferometric beam before being detected by a linear array CCD, the lateral resolution in the other direction can be less than 0.8 μm. The wavelength of the light reflected from each measured point on the surface is unvariable and the measurement results can be wavelength-traceable exactly.